Tekkit and Attack of the B-Team will not launch? [closed]

1 & 2: I'm using the Tekkit and Attack of the B-Team modpacks from the Technic Launcher. Their current Minecraft versions are both 1.6.4 I think.

3: The following log is from my "logs" folder when I search %appdata% and open the .technic folder - from today when I tried to launch Tekkit: http://paste.ubuntu.com/9374783/

The end part where the error occurs:

[B#439] 2014/12/03 13:53:41 [INFO]  2014-12-03 13:53:41 [WARNING] [ForgeModLoader] The coremod codechicken.core.launch.DepLoader does not have a MCVersion annotation, it may cause issues with this version of Minecraft
[B#439] 2014/12/03 13:53:41 [INFO]  2014-12-03 13:53:41 [INFO] [ForgeModLoader] Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker
[B#439] 2014/12/03 13:53:41 [INFO]  2014-12-03 13:53:41 [INFO] [ForgeModLoader] Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker
[B#439] 2014/12/03 13:53:41 [INFO]  2014-12-03 13:53:41 [INFO] [ForgeModLoader] Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker
[B#439] 2014/12/03 13:53:41 [INFO]  2014-12-03 13:53:41 [SEVERE] [ForgeModLoader] Unable to launch
[B#439] 2014/12/03 13:53:41 [INFO]  java.util.ConcurrentModificationException
[B#439] 2014/12/03 13:53:41 [INFO]      at java.util.ArrayList$Itr.checkForComodification(Unknown Source)
[B#439] 2014/12/03 13:53:41 [INFO]      at java.util.ArrayList$Itr.remove(Unknown Source)
[B#439] 2014/12/03 13:53:41 [INFO]      at net.minecraft.launchwrapper.Launch.launch(Launch.java:114)
[B#439] 2014/12/03 13:53:41 [INFO]      at net.minecraft.launchwrapper.Launch.main(Launch.java:27)
[B#439] 2014/12/03 13:53:42 [INFO]  Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=256m; support was removed in 8.0
[B#439] 2014/12/03 13:54:21 [INFO] Maximum usable memory detected: 3978 mb
[B#439] 2014/12/03 14:18:59 [INFO] ------------------------------------------
[B#439] 2014/12/03 14:18:59 [INFO] Technic Launcher is starting....
[B#439] 2014/12/03 14:18:59 [INFO] Launcher Build: 439
[B#439] 2014/12/03 14:18:59 [INFO] ------------ Startup Parameters ------------
[B#439] 2014/12/03 14:18:59 [INFO] --------- End of Startup Parameters ---------
[B#439] 2014/12/03 14:18:59 [INFO] Analytics Response [runLauncher]: 200
[B#439] 2014/12/03 14:19:01 [INFO] {"accessToken":"5c559bb7e0ed418c94d8cd60ef77d77a","clientToken":"d71edf1b-160b-43d9-9f21-2e7a72a7eec1","selectedProfile":{"id":"f0be942e14da46c79ddf4a9eabf2269d","name":"QUOFFEE"}}
[B#439] 2014/12/03 14:19:01 [INFO] Launcher took: 2102ms to start
[B#439] 2014/12/03 14:19:01 [INFO] Pack: tekkitmain Image Download Worker Calculated MD5: bccfd794ff80c03dae9424a0cc0eda5f Required MD5: f39ae618809383451f6832e4d2a738fe
[B#439] 2014/12/03 14:19:01 [INFO] Starting download of http://cdn.technicpack.net/resources/tekkitmain/background.png?1410213214, with 3 tries remaining
[B#439] 2014/12/03 14:19:01 [INFO] Pack: tekkitmain Image Download Worker Calculated MD5: f9a822f3a2997db95806f0175da24e32 Required MD5: 1dd87c03268a7144411bb8cbe8bf7326
[B#439] 2014/12/03 14:19:01 [INFO] Starting download of http://cdn.technicpack.net/resources/tekkitmain/icon.png?1410213214, with 3 tries remaining
[B#439] 2014/12/03 14:19:01 [INFO] Pack: hexxit Image Download Worker Calculated MD5: 418def033519963168abd7a0d2189d36 Required MD5: 1426f5b19df42eab2cabbaa34823c8c9
[B#439] 2014/12/03 14:19:01 [INFO] Starting download of http://cdn.technicpack.net/resources/hexxit/logo.png?1414112755, with 3 tries remaining
[B#439] 2014/12/03 14:19:42 [INFO] Maximum usable memory detected: 3978 mb

4: Computer specs... All I know is it's a 64-bit Windows 7. Where can I find other stuff?

5: AotBT kept running out of memory and I found out that to solve this, I could allocate more RAM using the gear at the top-right of the Technic Launcher. However, I had to get 64-bit Java to add more than just 1 GB. I downloaded JRE 8 release 25 to solve this, and immediately allocated 2 GB instead of 1. Ever since then, the launcher has disappeared after hitting "Play" as usual, but it has reappeared a few seconds after and no game is launched. The exact same thing happens with Tekkit.

6: I tried uninstalling the 32-bit Java 7 that I previously used, but that didn't work. The same issue keeps happening. Being not all that good at fixing this stuff, I don't know what else to do.

I'd like to know how to fix this issue so I can play these modpacks, as they are my favorite packs in the Technic Launcher.