The rigging should really be a "one-click" thing if everything is zeroed correctly. You're figure might be breaking because the bones and bend zones are not properly aligned with the geometry... something must have shifted... that is all I can imagine.

Load M4 and zero it and then load the M4 RR geometry to see if they really are lined up correctly. I would hate to think you would need to rebuild your M4 RR from the start! These V4 RR and M4 RR are terrific figures to have.