Comment 7 for bug 1020227

Have you tried to perform a clean install?

If often do wonders with any software (although, it didn't help me with this exact problem when I encountered it):

1) Do a backup of whatever temp. files that you might need/want.
2) Make sure qBittorrent isn't running (check your running processes via Windows Task Manager).
3) Uninstall old qBittorrent version.
4) Reboot.
5) Delete these folders (if they exist):
C:\Program Files\qBittorrent (or its equivalent on other Windows versions)
C:\Documents and Settings\*****\Application Data\qBittorrent (or its equivalent on other Windows versions)
C:\Documents and Settings\*****\Local Settings\Application Data\qBittorrent (or its equivalent on other Windows versions)
6) Delete this reg. string (if it exist):
HKEY_LOCAL_MACHINE\SOFTWARE\qbittorrent
7) Install new qBittorrent version.
8) Reboot.