Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)
I would check out this thread over at xbmc.org:
http://forum.xbmc.org/showthread.php?t=98493
Sounds like people are having problems with 4.3.1. I am going to downgrade to 4.2 - I think.
The last time I upgraded, I went from an old AppleTV to the new one and I exported my library (in Settings - somewhere). That created thumbs & nfo files which the new version picked up during "scan for new content". But I did have to recreate all of my custom settings etc in XBMC. This time I backed up the "preferences" directory which in theory (as I understand it) would allow me to bypass that step. I say "in theory" because I had problems with (of my own creation- by way of an add-on) that I don't want to carry forward.