Problem with model exporting

Hi guys,
sometimes when I export reference .SMD, I have this problem: http://i.imgur.com/lemFm.png
I don’t know how to fix it…
Can you help me?

This is a problem with the weightmap on the model. You should check the bone weights on these spots. What program are you using?

I’m using 3DS Max

Alright, then check the vertex or bone weights on these spots.

Ok, thx!