Mudbox painting issues

Cheathem

Hey guys and gals,im having a really annoying problem right now.
Mud box wont let me paint on certain parts of a mesh with a small brush.
No clue why d:
Ive messed with camera clipping with no results.

Heres whats happening
http://i.imgur.com/ohhAx.png

hope you guys can help.

Thanks.

Cheathem

nvrm guys,exporting the base mesh as a fbx solved the problem.sorry for the useless post