Setup room can be tricky in Poser I remember that SM fixed some issues on the last Poser 11 update due crashes when changing the Hierarchy order on a model. Crashes normally occur if you try changing an upper part of a Hierarchy chain reparenting them to another body part it is where a crash might happen. In my case I even had crashes that caused the Licence to blow off using the Setup room. SM gave me support at the time to get a stable Infinite Licence ! really bad crashes can happen if you Move or delete a single bone in the hierarchy chain that is not last having attached bones on it .

In your case as I can't see the Hierarchy you actually have and how you want to change it you might consider rebuilding it. On Models I create I use bridges with Blender, Hierarchy Bone and Modeling surface issues are fixed in Blender sending it back to Poser from there i just copy Paste the rigging that already was done back to the model, this way I do not have to re rig the whole thing and can move on from the latest point .