Where are my faces??

Just when I got my model all done and textured, Unity gives me a huge kick in the nuts. When I imported my Mesh some 20% of the faces have become invisible (As seen in the below picture), and also the animation is messed up :(. I tried to find out why but I am stumped. Cant find any reasons.



But at lest I got a the mesh all textured and animated, and I am pretty happy with it : )