I had the same problem with utorrent. I went through every forum I could find making all the changes without any result. I don't know what the problem is, only that alot of people where having it.
The solution according to me: Unistall uTorrent and install BitCommet
::: BitCommet is the fastes torrent client today (there are tests on this on the internet)
This solved my problem.
I can say that I used BitCommet before and choosed to go with uTorrent because the Commet crashed alot. However, the latest build that I downloaded today seem to be quite stable.