One thingis ProE will allow you to move a parent into the subassembly and leave the children in thetop level assembly. If you try to move the parent from the subassembly back to the top level assembly ProE won't do it because ittries to place the parent after the child. You should see a message to the effect that the restructure was aborted due to attempts to place a parent after a child. If that's the case try to figure out what parts are children, move them to the subassembly, then try and use restructure and see if it lets you move the parts to the top level. Also check to see if you have a circular reference file.
Edited by: kdem