Animating Havoc.

So, I’ve created this suit of armor and rigged it. The suit is made up of several different pieces, each of which is a separate mesh. I then parented all the pieces to individual bones on my rig. So I thought it was ready, made a walk cycle to test it out and loaded it into the NLA editor and everything worked fine, except for a problem with the IK constraints on the foot. I couldn’t find the problem, so I put my model beck in rest pose and wiped the walk cycle. I then basically deleted the entire leg and that portion of the rig and did a mirror copy of the other one and fixed up the constraints again. So that done I decided to animate my model in some different poses. That’s when things went wild. Every time I would ctl-z an action, some part of my mesh would go flying away from the bone. I would fix it, advance some frames, animate, and it would happen again. So basically if I scrub through the animation I looks like my model is exploding to pieces. I am not sure what the freak is going on. Perhaps there are some key frames that where applied to the mesh as I was animating the walk cycle or something. Is there a way to clear all existing keys with a button or something? Anybody have any solutions before I go insane?

is the chain length for the IK constraints set?
post some screen shots and/or the blend.