I've installed Ubuntu and Lubuntu a few times now and some of those times I've had the following problem, which I currently have. When I click a torrent magnet link in Chrome (usually from Pirate bay), instead of opening transmission, the only thing that happens is a new Chrome window opens.
Upon other installations, I've not had this problem; transmission opened just as I'd like.
I've tried using Chrome's extension .torrent to Transmission, but I get the error
unable to contact http ://localhost:9091/transmission/rpc