Forum:Internal error: Could not copy file

when i try to upload an image i get the message:

Internal error

Could not copy file "/images/warhammeronline/images/temp/5/5b/20070830205624!MAP_ChaosWastes.jpg" to "/images/warhammeronline/images/5/5b/MAP_ChaosWastes.jpg". Retrieved from "http://warhammeronline.wikia.com/wiki/Special:Upload"

whats the problem?