I finally got mine working through the trick freakachu is talking about in this thread
http://forums.technicpack.net/index.php/topic,5184.msg30670.html#msg30670
I had tried it before without any luck, but I messed around with it a bit and it finally opened. Just thought I'd let you know.
Thanks for the help
Tried it, this is all I got:
Maybe I fucked it up or something, but there doesn't seem to be anything happening there at all
EDIT: I realised afterwards that I had linked straight to the .jar instead of the .exe. But I tried with the .exe and it looked exactly the same except the filename ending with exe.
Exactly the same problem here. 64-bit, no antivirus, tried reinstalling Java countless times with different versions. Tried opening the jar file, tried replacing the jar file and opening again, etc.