I'm currently making models for a RPG game, someone else is doing the animations. When I get the animated PZ3 file back I get.... yep sliding feet. All I do is open the PZ3 in an editor and delete the x, y and z Translate data in the channels section of both feet. This cures the problem and the animation works correctly.
Not saying that this is the full solution, but it works for what I am doing.