Every time I want to start the modpack, it doesn't work. This is what it says in the console:
Logging in...
Beginning authlib authentication attempt
successfully created YggdrasilAuthenticationService
Login complete.
Checking local assets file, for MC version1.7.10 Please wait!
Setting up native libraries for Blast Off! v 1.1.17 MC 1.7.10
Syncing Assets:
Java Path: C:\Program Files\Java\jre1.8.0_31\bin\javaw.exe
Pack: Blast Off! 1.7.10
Setting MinMemory to 256
Setting MaxMemory to 3072
Defaulting PermSize to 256m
[21:36:05] [main/INFO]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[21:36:05] [main/ERROR]: Unable to launch
java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.8.0_31]
at java.net.URLClassLoader$1.run(Unknown Source) ~[?:1.8.0_31]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_31]
at java.net.URLClassLoader.findClass(Unknown Source) ~[?:1.8.0_31]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:106) ~[launchwrapper-1.11.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_31]
at java.lang.Class.forName0(Native Method) ~[?:1.8.0_31]
at java.lang.Class.forName(Unknown Source) ~[?:1.8.0_31]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:98) [launchwrapper-1.11.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.11.jar:?]
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option PermSize=256m; support was removed in 8.0
I'm using Java 1.8.0_31 and WIndows 7 64-Bit. Can somebody please help me?