Attachment Points

When I go in to user properties, and I try to apply: "Attachment Point"
It gives me an error that basically says "Something critical happened and 3ds will now close"
And it almost literally says "something". It does not give me specific information, just "something"

I need attachment points to reduce the ammount of animations I have to do (for repairing units etc.)
I uninstalled and reinstalled wc3 art tools and no luck...
Tried it on max4 and max5, same thing.
Is there a special process I need to do?