Windows .jar Unable to launch some modpacks & world save crashes game

[Brandon99901]

occasionally when i launch FTB one or more modpacks won't launch. It doesn't matter what modpack i start it just sometimes won't launch, other times it does. The only distinguishable difference from when i launch the modpack is i had restarted my computer.What i would really like is if someone can tell me of a way to fix this problem so i can launch any modpack instead of just the madpacks the i am limited to.

Here is my pastebin;
http://pastebin.com/ZDVTFn24

Another problem has happened where i try to open my FTB world in direwolf20 1.6.4 pack and the game crashes

Pastebin
http://pastebin.com/Kn8MPKWZ

 

[JamiePhonic]

the first pastebin, i'm not sure of. the only thing i can tell you is that a class appears to be missing.

java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker

as for your crash, it appears to be related to enderstorage, specifically, one of the files it uses is corrupt, which is easily fixed

goto: <FTB INSTALL_DIR>/<MODPACK NAME>/minecraft/saves/<WORLD NAME>/EnderStorage
and delete the files in there. you will loose the content of any ender chests you have though.

so if you installed FTB in c:\FTB, you would go to: c:\FTB\<MODPACK NAME>\minecraft\saves\<WORLD NAME>\EnderStorage

 

[Brandon99901]

this stopped the game crashing upon clicking load world but now it crashes after the world loads (after the games loading world screen goes away)
New pastebin;
http://pastebin.com/Ge50hcE4

 

[JamiePhonic]

this sticks out:

2014-01-28 18:55:14 [WARNING] [ForgeModLoader] Unable to read forced chunk data at C:\Program Files (x86)\FTB\Direwolf20_1_6_4\minecraft\saves\Direwolf's world\DIM-1\forcedchunks.dat - it will be ignored
java.io.IOException: Root tag must be a named compound tag

NEVER install FTB to your Program Files Folder. it causes more trouble than its worth. change the install location to somewhere like your my documents folder or just the C drive (i.e. C:\FTB) then move the folder from program files to the new location to preserve your saves and settings. then delete the file

<INSTALL_DIR>\FTB\Direwolf20_1_6_4\minecraft\saves\Direwolf's world\DIM-1\forcedchunks.dat

 

[Brandon99901]

the problem persists after moving the folder here is the new pastebin log (sidenote this also doesn't fix the first problem in case you was wondering).
http://pastebin.com/WdVmy4qb
Note this isn't the full log as it was to much memory for pastebin

 

[JamiePhonic]

now one of your mystcraft ages is throwing a strop...

2014-01-28 20:36:22 [INFO] [STDOUT] java.lang.IllegalArgumentException: Empty string not allowed
2014-01-28 20:36:22 [INFO] [STDOUT] at net.minecraft.nbt.NBTTagString.<init>(SourceFile:15)
2014-01-28 20:36:22 [INFO] [STDOUT] at net.minecraft.nbt.NBTTagCompound.func_74778_a(SourceFile:81)
2014-01-28 20:36:22 [INFO] [STDOUT] at com.xcompwiz.mystcraft.world.agedata.AgeData.func_76187_b(AgeData.java:276)