Disappearing faces?
 

I have never had this problem before. Whenever I extrude, several faces disappear! A similar thing happened to me last month, but all I had to do was assign a blinn, and that isn't working this time. The faces will reappear randomly, or when I do the fill hole option on one of the holes, they all fill in. However, they will disappear again when I try to extrude. The mesh stays in place. Also, when I assign a material such as blinn to the whole thing, the faces that normally disappear stay lambert. I am very new to maya, I have only taken an intro class. Here are some screenshots of it http://i1110.photobucket.com/albums/...azier/help.png
Thanks! :help: