Mesh gets deformed when parented

So I have an armature with modelled bones attach to it, now when I try to parent a modelled skin to it as well the skin mesh gets deformed and quite hideous.

Here;s the blend

and here’s a screen of the thumb being parented.

ANy body know why?
I have a similar thread in animations but it’s not really an animation question



did u notice that all of the object in the blend file are duplicated ?
is that meant to be that way ?

Yeah, they where needed before, but I don’t need them anymore and I don’t know how to delete those datablocks.

anyone know why?