I don’t know how to explain it, so here is an example video. I model animate for Quake mods on the PlayStation Portable and have for some time, but I always run into this problem and I don’t remember how I fix it, if I have. I cannot redo what I just did so I need to know if there is a solution. I am using Blender 2.49b.
First try to check and see how many Armature modifiers are on your mesh. My guess is that you have two, and they’re doubling up.