If the library is undocked as a general preference, you should be using Adobe Air, not Flash, to power the feature especially under 64-bit OS.

Correct. Sorry, it was late. :) But, I had the same issue when an Adobe update hit my machine. All my thumbs were gone and they wouldn't cache. It was likely that I didn't have to reinstall and I could have just re-patched Poser to get the libraries to behave.