Cannot launch Killing Foor

[Errorsmakemesad]

Everytime I try to launch KF I get a Critical Error, and it says..

Build UT2004_Build_[2004-11-11_10.48]
OS: Windows NT 6.0 (Build: 6002)
CPU: AuthenticAMD Unknown processor @ 2699 MHz with 4095MB RAM
Video: ATI Radeon HD 3200 Graphics (630)
Could not spawn a GUI Controller!
History: UGameEngine::Init <- InitEngine <- FMallocWindows::Free <- FMallocWindows::Free

I used to have a quest pass, it ran perfectly fine. But I bought it today, and everytime I launch it, I get that error. Please help?

 

[Valken]

Verify the contents are valid, may be corrupted files.