I am getting this same issue; log file posted below.
I am running Avast and checked my firewall settings to allow this to work
I tried turning off my firewall and it made no difference.
This was working on 5/2/2013 but stopped working yesterday.
I tried using the most up to date launcher but that also failed with the results below.
I have "actual internet" with no problems.
2013/05/04 13:55:07 [iNFO] ------------------------------------------
2013/05/04 13:55:07 [iNFO] Technic Launcher is starting....
2013/05/04 13:55:07 [iNFO] Launcher Build: 0
2013/05/04 13:55:07 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:55:07 [iNFO] Relaunched with correct memory
2013/05/04 13:55:07 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:55:06 [iNFO] ------------------------------------------
2013/05/04 13:55:06 [iNFO] Technic Launcher is starting....
2013/05/04 13:55:06 [iNFO] Launcher Build: 0
2013/05/04 13:55:06 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:55:06 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:55:06 [iNFO] Attempting relaunch with 1024 mb of RAM
2013/05/04 13:55:06 [iNFO] Path to Launcher Jar: C:\Users\Wormfood\Mineshafter2\ms2-4.2.10\ms2-modded-ms2-techniclauncher.jar
2013/05/04 13:55:06 [iNFO] Restarting in StartupParameters.java: 127.0.0.1:9010
2013/05/04 13:55:11 [iNFO] Starting download of http://skins.technicpack.net/helm/[ms2]Wyrmfood12/100, with 3 tries remaining
2013/05/04 13:55:11 [iNFO] Launcher took: 5351ms to start
2013/05/04 13:55:21 [iNFO] Mod pack Build: 1.5.2 Minecraft Version: 1.5.2
2013/05/04 13:55:21 [iNFO] Minecraft: 1.5.2 md5: 6897c3287fb971c9f362eb3ab20f5ddd use_patch: false
2013/05/04 13:55:21 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 3 tries remaining
2013/05/04 13:55:21 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:55:21 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 2 tries remaining
2013/05/04 13:55:21 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:55:21 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 1 tries remaining
2013/05/04 13:55:21 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:55:24 [sEVERE] java.lang.NullPointerException
2013/05/04 13:55:24 [sEVERE] at org.spoutcraft.launcher.GameUpdater.isFinished(GameUpdater.java:70)
2013/05/04 13:55:24 [sEVERE] at org.spoutcraft.launcher.GameLauncher.runGame(GameLauncher.java:131)
2013/05/04 13:55:24 [sEVERE] at org.spoutcraft.launcher.GameUpdater.runGame(GameUpdater.java:136)
2013/05/04 13:55:24 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginFrame.onEvent(LoginFrame.java:309)
2013/05/04 13:55:24 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginWorker.doInBackground(LoginWorker.java:103)
2013/05/04 13:55:24 [sEVERE] at org.jdesktop.swingworker.SwingWorker$1.call(Unknown Source)
2013/05/04 13:55:24 [sEVERE] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
2013/05/04 13:55:24 [sEVERE] at java.util.concurrent.FutureTask.run(Unknown Source)
2013/05/04 13:55:24 [sEVERE] at org.jdesktop.swingworker.SwingWorker.run(Unknown Source)
2013/05/04 13:55:24 [sEVERE] at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
2013/05/04 13:55:24 [sEVERE] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
2013/05/04 13:55:24 [sEVERE] at java.lang.Thread.run(Unknown Source)
2013/05/04 13:55:48 [iNFO] ------------------------------------------
2013/05/04 13:55:48 [iNFO] Technic Launcher is starting....
2013/05/04 13:55:48 [iNFO] Launcher Build: 0
2013/05/04 13:55:48 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:55:48 [iNFO] Relaunched with correct memory
2013/05/04 13:55:48 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:55:47 [iNFO] ------------------------------------------
2013/05/04 13:55:47 [iNFO] Technic Launcher is starting....
2013/05/04 13:55:47 [iNFO] Launcher Build: 0
2013/05/04 13:55:47 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:55:47 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:55:47 [iNFO] Attempting relaunch with 1024 mb of RAM
2013/05/04 13:55:47 [iNFO] Path to Launcher Jar: C:\Users\Wormfood\Mineshafter2\ms2-4.2.11\ms2-4.2.11\ms2-techniclauncher.jar
2013/05/04 13:55:47 [iNFO] Restarting in StartupParameters.java: null:null
2013/05/04 13:55:55 [iNFO] Starting download of http://skins.technicpack.net/helm/[ms2]Wyrmfood12/100, with 3 tries remaining
2013/05/04 13:55:56 [iNFO] Launcher took: 9041ms to start
2013/05/04 13:56:30 [iNFO] ------------------------------------------
2013/05/04 13:56:30 [iNFO] Technic Launcher is starting....
2013/05/04 13:56:30 [iNFO] Launcher Build: 0
2013/05/04 13:56:30 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:56:30 [iNFO] Relaunched with correct memory
2013/05/04 13:56:30 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:56:29 [iNFO] ------------------------------------------
2013/05/04 13:56:29 [iNFO] Technic Launcher is starting....
2013/05/04 13:56:29 [iNFO] Launcher Build: 0
2013/05/04 13:56:29 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:56:29 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:56:29 [iNFO] Attempting relaunch with 1024 mb of RAM
2013/05/04 13:56:29 [iNFO] Path to Launcher Jar: C:\Users\Wormfood\Mineshafter2\ms2-4.2.11\ms2-4.2.11\ms2-modded-ms2-techniclauncher.jar
2013/05/04 13:56:29 [iNFO] Restarting in StartupParameters.java: 127.0.0.1:9010
2013/05/04 13:56:34 [iNFO] Starting download of http://skins.technicpack.net/helm/[ms2]Wyrmfood12/100, with 3 tries remaining
2013/05/04 13:56:34 [iNFO] Launcher took: 5247ms to start
2013/05/04 13:56:40 [iNFO] Mod pack Build: 1.5.2 Minecraft Version: 1.5.2
2013/05/04 13:56:40 [iNFO] Minecraft: 1.5.2 md5: 6897c3287fb971c9f362eb3ab20f5ddd use_patch: false
2013/05/04 13:56:40 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 3 tries remaining
2013/05/04 13:56:40 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:56:40 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 2 tries remaining
2013/05/04 13:56:40 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:56:40 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 1 tries remaining
2013/05/04 13:56:40 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:56:42 [sEVERE] java.lang.NullPointerException
2013/05/04 13:56:42 [sEVERE] at org.spoutcraft.launcher.GameUpdater.isFinished(GameUpdater.java:70)
2013/05/04 13:56:42 [sEVERE] at org.spoutcraft.launcher.GameLauncher.runGame(GameLauncher.java:131)
2013/05/04 13:56:42 [sEVERE] at org.spoutcraft.launcher.GameUpdater.runGame(GameUpdater.java:136)
2013/05/04 13:56:42 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginFrame.onEvent(LoginFrame.java:309)
2013/05/04 13:56:42 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginWorker.doInBackground(LoginWorker.java:103)
2013/05/04 13:56:42 [sEVERE] at org.jdesktop.swingworker.SwingWorker$1.call(Unknown Source)
2013/05/04 13:56:42 [sEVERE] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
2013/05/04 13:56:42 [sEVERE] at java.util.concurrent.FutureTask.run(Unknown Source)
2013/05/04 13:56:42 [sEVERE] at org.jdesktop.swingworker.SwingWorker.run(Unknown Source)
2013/05/04 13:56:42 [sEVERE] at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
2013/05/04 13:56:42 [sEVERE] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
2013/05/04 13:56:42 [sEVERE] at java.lang.Thread.run(Unknown Source)
2013/05/04 13:57:32 [iNFO] ------------------------------------------
2013/05/04 13:57:32 [iNFO] Technic Launcher is starting....
2013/05/04 13:57:32 [iNFO] Launcher Build: 0
2013/05/04 13:57:32 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:57:32 [iNFO] Relaunched with correct memory
2013/05/04 13:57:32 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:57:31 [iNFO] ------------------------------------------
2013/05/04 13:57:31 [iNFO] Technic Launcher is starting....
2013/05/04 13:57:31 [iNFO] Launcher Build: 0
2013/05/04 13:57:31 [iNFO] ------------ Startup Parameters ------------
2013/05/04 13:57:31 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 13:57:31 [iNFO] Attempting relaunch with 1024 mb of RAM
2013/05/04 13:57:31 [iNFO] Path to Launcher Jar: C:\Users\Wormfood\Mineshafter2\ms2-4.2.10\ms2-modded-ms2-techniclauncher.jar
2013/05/04 13:57:31 [iNFO] Restarting in StartupParameters.java: 127.0.0.1:9010
2013/05/04 13:57:36 [iNFO] Starting download of http://skins.technicpack.net/helm/[ms2]Wyrmfood12/100, with 3 tries remaining
2013/05/04 13:57:36 [iNFO] Launcher took: 5049ms to start
2013/05/04 13:57:48 [iNFO] Mod pack Build: 1.5.2 Minecraft Version: 1.5.2
2013/05/04 13:57:48 [iNFO] Minecraft: 1.5.2 md5: 6897c3287fb971c9f362eb3ab20f5ddd use_patch: false
2013/05/04 13:57:48 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 3 tries remaining
2013/05/04 13:57:48 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:57:48 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 2 tries remaining
2013/05/04 13:57:48 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:57:48 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 1 tries remaining
2013/05/04 13:57:49 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:57:52 [sEVERE] java.lang.NullPointerException
2013/05/04 13:57:52 [sEVERE] at org.spoutcraft.launcher.GameUpdater.isFinished(GameUpdater.java:70)
2013/05/04 13:57:52 [sEVERE] at org.spoutcraft.launcher.GameLauncher.runGame(GameLauncher.java:131)
2013/05/04 13:57:52 [sEVERE] at org.spoutcraft.launcher.GameUpdater.runGame(GameUpdater.java:136)
2013/05/04 13:57:52 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginFrame.onEvent(LoginFrame.java:309)
2013/05/04 13:57:52 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginWorker.doInBackground(LoginWorker.java:103)
2013/05/04 13:57:52 [sEVERE] at org.jdesktop.swingworker.SwingWorker$1.call(Unknown Source)
2013/05/04 13:57:52 [sEVERE] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
2013/05/04 13:57:52 [sEVERE] at java.util.concurrent.FutureTask.run(Unknown Source)
2013/05/04 13:57:52 [sEVERE] at org.jdesktop.swingworker.SwingWorker.run(Unknown Source)
2013/05/04 13:57:52 [sEVERE] at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
2013/05/04 13:57:52 [sEVERE] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
2013/05/04 13:57:52 [sEVERE] at java.lang.Thread.run(Unknown Source)
2013/05/04 13:58:21 [iNFO] Maximum usable memory detected: 1024 mb
2013/05/04 13:59:28 [iNFO] Mod pack Build: 1.5.2 Minecraft Version: 1.5.2
2013/05/04 13:59:28 [iNFO] Minecraft: 1.5.2 md5: 6897c3287fb971c9f362eb3ab20f5ddd use_patch: false
2013/05/04 13:59:28 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 3 tries remaining
2013/05/04 13:59:28 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:59:28 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 2 tries remaining
2013/05/04 13:59:29 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:59:29 [iNFO] Starting download of http://assets.minecraft.net/1_5_2/minecraft.jar, with 1 tries remaining
2013/05/04 13:59:29 [sEVERE] Download of http://assets.minecraft.net/1_5_2/minecraft.jar Failed!
2013/05/04 13:59:52 [sEVERE] java.lang.NullPointerException
2013/05/04 13:59:52 [sEVERE] at org.spoutcraft.launcher.GameUpdater.isFinished(GameUpdater.java:70)
2013/05/04 13:59:52 [sEVERE] at org.spoutcraft.launcher.GameLauncher.runGame(GameLauncher.java:131)
2013/05/04 13:59:52 [sEVERE] at org.spoutcraft.launcher.GameUpdater.runGame(GameUpdater.java:136)
2013/05/04 13:59:52 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginFrame.onEvent(LoginFrame.java:309)
2013/05/04 13:59:52 [sEVERE] at org.spoutcraft.launcher.skin.components.LoginWorker.doInBackground(LoginWorker.java:103)
2013/05/04 13:59:52 [sEVERE] at org.jdesktop.swingworker.SwingWorker$1.call(Unknown Source)
2013/05/04 13:59:52 [sEVERE] at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
2013/05/04 13:59:52 [sEVERE] at java.util.concurrent.FutureTask.run(Unknown Source)
2013/05/04 13:59:52 [sEVERE] at org.jdesktop.swingworker.SwingWorker.run(Unknown Source)
2013/05/04 13:59:52 [sEVERE] at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
2013/05/04 13:59:52 [sEVERE] at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
2013/05/04 13:59:52 [sEVERE] at java.lang.Thread.run(Unknown Source)
2013/05/04 14:26:08 [iNFO] ------------------------------------------
2013/05/04 14:26:08 [iNFO] Technic Launcher is starting....
2013/05/04 14:26:08 [iNFO] Launcher Build: 0
2013/05/04 14:26:08 [iNFO] ------------ Startup Parameters ------------
2013/05/04 14:26:08 [iNFO] Relaunched with correct memory
2013/05/04 14:26:08 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 14:26:07 [iNFO] ------------------------------------------
2013/05/04 14:26:07 [iNFO] Technic Launcher is starting....
2013/05/04 14:26:07 [iNFO] Launcher Build: 0
2013/05/04 14:26:07 [iNFO] ------------ Startup Parameters ------------
2013/05/04 14:26:07 [iNFO] --------- End of Startup Parameters ---------
2013/05/04 14:26:07 [iNFO] Attempting relaunch with 1024 mb of RAM
2013/05/04 14:26:07 [iNFO] Path to Launcher Jar: C:\Users\Wormfood\Mineshafter2\ms2-4.2.10\ms2-modded-ms2-techniclauncher.jar
2013/05/04 14:26:07 [iNFO] Restarting in StartupParameters.java: 127.0.0.1:9010
