Armature Problem

why is this

http://img526.imageshack.us/img526/5934/armaturesa1.png

happening. it seems the instead of the verts sticking to the armature they are deforming as it moves. is there a setting to fix this?

I generally use armatures with vertex groups, so I can tell blender exactly which vertices will be 100% influenced by a bone.

yeah. my problem is that its deforming a vertex group

it works when i append the object to another .blend and rearmature it. i have no idea why

The best solution I have found to this problem is moving the axis of the armature bones… joints too close to surface meshes are always a problem…hope that helps…