I have the same really anoying problem but me it's on the technic pack I searched everywhere and this is the only topic I found about that. I am also using a win7 64bit and a java 7. I don't even know why this is ending with somnia, I wasn't even near a bed.
Here is the log:
[23:35:59] [sEVERE] (MAtmos : INFO) ExpansionLoader found potential online interactions_extras.xrl.
[23:35:59] [sEVERE] Mod Loaded: "mod_MAtmos_forModLoader r10 for 1.1.x"
[23:35:59] [sEVERE] Mod Loaded: "mod_Millenaire 2.3.1"
[23:35:59] [sEVERE] Mod Loaded: "mod_mocreatures v3.2.2 (MC 1.1)"
[23:35:59] [sEVERE] Mod Loaded: "mod_IC2_ChargingBench 1.64-1"
[23:35:59] [sEVERE] addOverride(/gui/items.png,/tome.png,171). 62 left.
[23:35:59] [sEVERE] Mod Loaded: "Tome mod by pinkemma"
[23:35:59] [sEVERE] Mod Loaded: "XP book mod by pinkemma"
[23:35:59] [sEVERE] addOverride(/terrain.png,/Zeppelin/front.png,186). 33 left.
[23:35:59] [sEVERE] addOverride(/terrain.png,/Zeppelin/back.png,187). 32 left.
[23:35:59] [sEVERE] addOverride(/terrain.png,/Zeppelin/top.png,188). 31 left.
[23:35:59] [sEVERE] addOverride(/terrain.png,/Zeppelin/compass.png,189). 30 left.
[23:35:59] [sEVERE] addOverride(/gui/items.png,/Zeppelin/radio.png,176). 61 left.
[23:35:59] [sEVERE] Rotation data loaded so far: 0
[23:35:59] [sEVERE] Starting reading rotation data from "\technicssp\config\MetaRotation\Vanilla.meta"
[23:35:59] [sEVERE] Finished reading rotation data from "\technicssp\config\MetaRotation\Vanilla.meta"
[23:35:59] [sEVERE] Rotation data loaded so far: 290
[23:35:59] [sEVERE] Mod Loaded: "mod_Zeppelin 1.1.0.0.25"
[23:35:59] [sEVERE] Mod Loaded: "mod_NetherOres 1.1.0R1.1.2"
[23:35:59] [sEVERE] (MAtmos : INFO) ExpansionLoader fetched interactions_environments.xrl.
[23:35:59] [sEVERE] (MAtmos : INFO) ExpansionLoader fetched earthlies_database.xrl.
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreCopper, id=249 meta=0
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherCoal, id=135 meta=0
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherCopper, id=135 meta=6
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherDiamond, id=135 meta=1
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherGold, id=135 meta=2
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherIron, id=135 meta=3
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherLapis, id=135 meta=4
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherRedstone, id=135 meta=5
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreNetherTin, id=135 meta=7
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreTin, id=248 meta=0
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreUranium, id=247 meta=0
[23:35:59] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: woodRubber, id=243 meta=0
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftAutomation 3.3.1"
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftBuildcraft 3.3.1"
[23:35:59] [sEVERE] Railcraft Core Module: Bronze detected, adding alternative minecart recipe: ingotBronze, id=30 246
[23:35:59] [sEVERE] Railcraft Core Module: Bronze detected, adding alternative minecart recipe: ingotBronze, id=5 261
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftCore 3.3.1"
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftExtras 3.3.1"
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftFactory 3.3.1"
[23:35:59] [sEVERE] Railcraft IC2 Module: Tin detected, adding Energy Detector recipe: id=30 247
[23:35:59] [sEVERE] Railcraft IC2 Module: Tin detected, adding Energy Detector recipe: id=5 260
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftIC2 3.3.1"
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftInfrastructure 3.3.1"
[23:35:59] [sEVERE] (MAtmos : INFO) ExpansionLoader fetched interactions_extras.xrl.
[23:35:59] [sEVERE] (MAtmos : INFO) ExpansionLoader Limbo is now empty.
[23:35:59] [sEVERE] Railcraft Factory Module: Bronze detected, adding alternative recipes: ingotBronze, id=30 246
[23:35:59] [sEVERE] Railcraft Factory Module: Bronze detected, adding alternative recipes: ingotBronze, id=5 261
[23:35:59] [sEVERE] Railcraft Factory Module: Refined Iron detected, adding alternative recipes: ingotRefinedIron, id=30 249
[23:35:59] [sEVERE] Mod Loaded: "mod_RailcraftRails 3.3.1"
[23:35:59] [sEVERE] Mod Loaded: "mod_ThaumCraft 1.2.5"
[23:35:59] [sEVERE] Mod Loaded: "mod_treecapitator 1.1"
[23:35:59] [sEVERE] Mod Loaded: "Balkon's WeaponMod 1.1.0 v8.4.0 SMP Edition"
[23:35:59] [sEVERE] Mod Loaded: "WirelessRedstone 1.5"
[23:35:59] [sEVERE] Mod Loaded: "WirelessRedstone 1.5"
[23:36:00] [sEVERE] Railcraft IC2 Module: Tin detected, adding Energy Detector recipe: id=1 257
[23:36:01] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreSilver, id=140 meta=3
[23:36:01] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreTin, id=140 meta=4
[23:36:01] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreCopper, id=140 meta=5
[23:36:01] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: woodRubber, id=143 meta=0
[23:36:03] [sEVERE] Starting BuildCraft 3.1.3
[23:36:03] [sEVERE] Copyright © SpaceToad, 2011
[23:36:03] [sEVERE] http://www.mod-buildcraft.com
[23:36:03] [sEVERE] blockABOPipeID set to 200
[23:36:03] [sEVERE] pipeLiquidsValveID set to 10200
[23:36:03] [sEVERE] pipeLiquidsGoldenIronID set to 10201
[23:36:03] [sEVERE] pipeLiquidsBalanceID set to 10203
[23:36:03] [sEVERE] pipeLiquidsDiamondID set to 10204
[23:36:03] [sEVERE] pipeItemsRoundRobinID set to 10300
[23:36:03] [sEVERE] pipeItemsCompactorID set to 10301
[23:36:03] [sEVERE] pipeItemsInsertionID set to 10302
[23:36:03] [sEVERE] pipeItemsExtractionID set to 10303
[23:36:03] [sEVERE] pipeItemsBounceID set to 10304
[23:36:03] [sEVERE] pipeItemsCrossoverID set to 10305
[23:36:03] [sEVERE] pipePowerSwitchID set to 10400
[23:36:03] [sEVERE] triggerEngineControlID set to 128
[23:36:04] [sEVERE] Additional pipes detected, adding compatibility
[23:36:04] [sEVERE] LogisticsPipes: got texture id 159 for supplier texture
[23:36:04] [sEVERE] RegisterGUI error: inventoryType already registered.
[23:36:04] [sEVERE] Using buildcraft.energy.PneumaticPowerFramework as framework.
[23:36:04] [sEVERE] Registering ore apatite.
[23:36:04] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreApatite, id=198 meta=0
[23:36:04] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreCopper, id=198 meta=1
[23:36:04] [sEVERE] Railcraft Automation Module: Ore Detected, adding to blocks Tunnel Bore can mine: oreTin, id=198 meta=2
[23:36:04] [sEVERE] Skipped plugin class forestry.plugins.PluginTwilightForest because preconditions were not met.
[23:36:06] [sEVERE] Initialized
[23:36:08] [sEVERE] (MAtmos : INFO) SoundCommunicator loaded (after 8.688 s.).
[23:36:08] [sEVERE] (MAtmos : INFO) Bypassing Resource Reloader. This may cause issues.
[23:36:08] [sEVERE] (MAtmos : INFO) ResourceReloader finished (after 8.774 s.).
[23:36:08] [sEVERE] (MAtmos : INFO) Ready.
[23:36:08] [sEVERE] (MAtmos : INFO) ExpansionLoader signaled. Currently has 3 expansions and 0 in limbo.
[23:36:08] [sEVERE] (MAtmos : INFO) Expansion interactions_environments.xrl loaded.
[23:36:08] [sEVERE] (MAtmos : INFO) Expansion interactions_extras.xrl loaded.
[23:36:11] [sEVERE] (MAtmos : INFO) Expansion earthlies_database.xrl loaded.
[23:36:11] [sEVERE] (MAtmos : INFO) ExpansionLoader Loading and Limbo are now empty.
[23:36:31] [sEVERE] EquivalentExchange has loaded RP2 ores, plants, trees and stone blocks.
[23:36:31] [sEVERE] EquivalentExchange has loaded RP2 ores, plants, trees and stone blocks.
[23:36:32] [sEVERE] Railcraft Buildcraft Module 3.3.1: Buildcraft Detected, creating Tank Cart and Liquid Loader recipes.
[23:36:32] [sEVERE] Railcraft IC2 Module 3.3.1: IC2 Detected, creating MFE Cart and Energy Loader recipes.
[23:36:32] [sEVERE] (MAtmos : INFO) Update version found: 11
[23:40:31] [sEVERE] mod_Somnia: DynamicLights mod was not detected. Disabling LightCache/BlockCoord resets while sleeping.
I know the log is short but this is realy all I got. So far I tried to create new world to see if it was corupted but no, i tried to allocate more or less memory to the game but this is not the solution, I ran both the launcher and java in administrator mode but gained nothing.
I tested something else, and it seems to work for now but I don't know why. If I deactivate Matmos and stop the game from auto-replacing the stuff I use, it seems to work fine. I played 3 hours without crash. Then I closed the game by myself for the first time in weeks. I hope my little trick here help someone.
It finally crashed at 19:00 loosing all my work of the last 4 hours, I suppose that means I did not correct the problem, I only achieved to delay it.