Lumpous

This is a repost of something madbrad21 posted on the tracker a few days ago, I figured it was really helpful to have so I'm reposting it here, thank madbrad for this, not me    
If you've got none of those (sometimes you won't if it's crashed in the launcher before starting minecraft), you can find the launcher logs by clicking on the cog in the top right of the Technic Launcher and clicking the logs button.  The latest file is usually the one you want.
 
Once you've got it, you can paste it here; http://paste.ubuntu.com/ and it'll give you a link which you can put in the forums (that makes reading it easier for us and also allows you to paste large amounts of info which you can't do on the forums).
 
 
If you've got a problem downloading a modpack (including attack of the B-Team). You'll find the most help here; http://forums.technicpack.net/tracker/project-1-technic-launcher/ If you can download it but not run it, you can find help for that here; http://forums.technicpack.net/tracker/project-4-attack-of-the-b-team/ If you can run it but you're struggling with something actually in the game, post here in this forum

Row 7 of your pastebin explains it all...

While having the launcher open and b-team selected on the left side, there is a gear below the "Attack of the B-Team" logo.
Click on it and select "Manually select a build". Then select your desired version from the dropdownmenu, press save and you are good to go.
 
The launcher will "up/downgrade" to the version you selected then.

Majority of the threads are stacking up with "MODPACK NO START HALP!" or "B-TEAM WORK NO MORE!" or the civilized "why is my Attack of the B-Team server not starting up anymore".
 
I am not backseat modding and I am not being rude. But this thread MORE THAN LIKELY will explain why all of a sudden it isn't working yet the previous version it was working fine.
 
Java6 support for one of the mods was dropped I believe and you need to get Java7 and install it. 
 
And make sure you REMOVE all aspects of Java6 before you just go an install Java7.

You are running an older version of Java.
Try updating to Java 7.