So, there can be, depending on the version of NEI and other mods running, a subtle crash where you can't open your inventory, it only occurs if you're running IC2 and NEI together and NEI1.1.1 at that.
This is because the creative inventory requires a player passed in during initialization, which doesn't exist when IC2 asks NEI to register IC2's extra stuff.
Attached is a patched nv.class file that fixes the problem with creative inventory so that NEI loads properly and you can play with full IC2 and NEI at the same time.
Hope it helps
And thanks to the mystery person who put up this pastebin: http://pastebin.com/ga6d5AQ9 which showed the broken IC2 init stacktrace.
And albaka can you fix the SubModule loading. You should use Class.forName() not loadClass- loadClass is an internal method of the ClassLoader system. There's a three arg Class.forName() which will do the job if you need to specify the classloader (which, by the way, you shouldn't). Also, allow for getting the stack trace from the failed mod init- it could be having side effects (see this post, right here). Perhaps use Logger.logexception() or something.
Hope this helps anyway.