HaloMods "Classic" Read-only Archive

Hey Guys, I'm using 3ds max 8 to edit some of the weapons in Halo PC, but 3ds max is doing something to the model that won't allow me to import it back into HMT, I know it's 3ds max because I can import anything that I have edited with milkshape just fine, Is there anyway to fix this problem?

Any Help would be greatly appreciated.

Thanks.[/i]