You have that problem where you start your download, but you get Cannot open torrent (stuff)\0.torrent or something?
This is an ownership problem.
Take ownership of the bitcomet folder (usually c:\program files\bitcomet)
Windows XP Home users - boot into safe mode (hold down f8 when you turn on your pc, until you get to a selection screen)
then, navigate to c:\program files, right click on bitcomet and go to security, and allow every user group full control over the folder, and it should work.