Player Model

I was wondering if anyone could tell me how to fix this problem which i have with the neck of a model when i replaced a head with a different one.

Screenshot
http://imageshack.us/photo/my-images/339/gmflatgrass0000w.jpg/

Thanks

what program are you using?

Milkshape but i also have 3ds max

Can you someone please advise?

I’m not a modeler but I think you should try and reposition the model or maybe change the skeleton a little bit.

You just have to fix the rigging and skeleton

Would someone be able to tell me how i would do this in Milkshape?

It looks like you need to set the weights. Look up mariokart’s ragdolling tutorials on Youtube, they really go in depth on the whole process of character creation for Gmod.