Hi LL...seems you are making progress of some sort.   You have much more knowledge of the program than I do so you might be able to help them solve the issue.   I'm seeing other threads popping up with similar disappearing library issues.   I'm sitting back and watching now since there was little I could do once I shared the screen captures.    I did notice a thread today discussing XL Library here:
http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2778635
...so I tried it and it is working beautifully for me.   I'm not a content creator, just a hobbyist, so it will meet my needs.  Guess I'll be out of the loop for future Poser upgrades, but that's the way things go.  

Yes, it's hard to say whether this is late night or early morning...haha.   I'm east coast US so it's a little past  5 a.m. here.  

I'll be stopping in to check on progress, I still may learn something from all this.   Have a good evening/early morning, whichever, and I'll check back tomorrow evening.

~skylab  : )