Firefox Portable Failing to Start - SOLVED

Trying to run Firefox Portable 2.0.0.14 from my USB drive. Splash screen displays then goes away - no Firefox!

Can't seem to find any error logs to help figure out why it's not running.

Running Windows XP Professional Version 2002 Service Pack 2.

Any help would be appreciated!

Installed to hard drive and then copied folder to USB drive and it worked. Not sure why, not sure I care.