[SallySimpson]

I had same prob after purchasing my new External HD and moving the foders with the music I was seeding to there.
I did the folowing: I put all the stuff I was seeding/leeching where they were before moving them (the folder selected for incoming stuff on UTorrent).
I deleted the torrents with error from my client, and I re-downloaded them from the trackers.
If the torrrents are not in the trackers any more for some reason, open them from C:/Doccumments and Settings/Administrator/Application Data/UTorrent.
(You need to see the hidden folders)

Your client will analize them and start seeding.
For some reason when I changed the location first time to re-downloaded them and rebooted, they got error. It seems it only works when you re-download them to the folder selected as default.
Hope it helps.