Engine Error -1 reply

I try to play the game and before I can do anything I get this Engine Error message,"Unable to init shader system." what's going on? System: HP Pavilion a706n 3000+ AMD Athlon Processor (2.1 Ghz) 512 RAM Don't know exact Video Card but has not been problem

What vid card you have makes all the difference. Either way. Uninstall current vid drivers reboot install updated vid drivers either from nvidia or ati and try that.