Ed wrote:Care to enlighten us on your OS? Your computer hardware? What graphics drivers you're running? Or shall we just guess?
Yay! My bet is on: Windows XP, HP Desktop, Pentium 4, 256 MB memory, Intel graphics, preloaded (default) graphics drivers
As shade11 said, you may not have all the proper files. If this occurs while you are playing online, it's probably a failed download. Otherwise, you may need to re-download the game if the files were corrupted previously.