Nod, have you got all the updates to Poser 11. I seem to recall there were some library problems when poser 11 came out, so that I had to load some items into a scene in poser 10 then save back to library to use them in poser 11, but this was overcome by later updates.

Are you saving into the default libraries? I know the poser manual says you can't delete the default libraries, but I found you can delete the downloads library and point to a previous downloads library. In this case if you try to put content into downloads as shown as the default it puts it into the old, deleted downloads, but if you use the drop down menu and select downloads then it puts it into the correct downloads library.