In the meantime, I took the time to install Windows XP and I am seeing your problem. Apparently the launch immediately terminates for some reason that I have not yet been able to track down. So I don't have any clue (yet) how to solve this.
To get Forge to work from the command prompt I also had to apply a service pack though. This was a JLine issue because JLine apparently uses some dll that is not installed in XP by default. I am suspecting the problem we are seeing is also due to something similar.
Regards,
Koen