Armatures stretching during rotation?! Help!

Heyy guys,

I’ve made a robot in Blender and it is made up of individual objects. I rigged these objects, one per bone. Now in pose mode, my bones (and meshes) are stretching when I rotate the bones! (IK disabled, maual rotation).

Help! :o

What kind of constraints are on the bones? Could you post a .blend?