check the disc see if it bad or has any crack or marks on it.
*un-install the game then delete the game folder totally!
*save any game files and maps you added to the game. and if you have mods for it save them too.
bad install is all, after you done all the things above then re-install the game and update date it.
update link:
http://www.novahq.net/?show=utilitie...et_file&id=211
play the game after it starts up look for update option in it to update it fully encase there a newer update to install online with novaworld service