I suggest you check the minimum system requirements for this game:
Operating System: Windows Vista Service Pack 1 / Windows XP Service Pack 3;
Processor: Intel Core 2 Duo 1.8 GHz, AMD Athlon X2 64 2.4 GHz;
Memory: 1.0 GB for Windows XP 1.5 GB for Windows Vista;
Hard Drive: 16 GB of free space;
Video Card: 256 MB Nvidia 7900 / 256 MB ATI X1900;
DirectX: DirectX 9.0c.
If this requirements are fulfilled, try to reinstall the game and if the problem persists, you will need to contact the provider.