Error Message
 

When playing Call to Duty and after the download wait for a new map. I'll receive the message Unpure client Invalid PK3 Files
How do I correct this problem, Tried unloading game and reinstalling but it does not eliminate the Error message from appearing about 30 percent of the time.
There was a typo mistake when I register my playing name is GRAMPA

i would think you have to get hold of the game maker or the service of it to clear it up. seem its on the server end of it, and not your end of it.