Well, what do ya know. Come home and try it again, everything works fine!

I did some digging on this issue, and it appears that dropping a tree onto the playlists section which contains .m3u files will cause the central to freeze (kinda) during the 'rebuilding database' phase.

After reconnecting, it says the playlists are bad, and deletes the links in them. Songs were still uploaded, and everything seems fine.

I uploaded the rest of my collection by dragging only the .mp3 files. Works great!

Another interesting note: the Rio Central will not play music while syncing, but a Rio Receiver can stream from it! Kinda strange..

--Bryan