-What's the resolution of the bitmap?
-What's its format? (.bmp? .jpg? .tga?)
-How much memory do you have and how high are your sampling settings?
You can see a few numbers in the image on the right....the 8, the 10....which means it's probably a memory issue.....although I'm not sure why a clockface would be generating memory errors :S....personally I've never had that problem.