I'm having the same issue on a XP SP3 system. It's the same useless error described by the original poster so it would be pointless to post it again. I've tried uninstalling normally and using Revo Uninstaller and each time rebooting... same result. It's a mystery but the application simply will not work with the task scheduler.
Has anyone else come up with another solution? Reinstalling the OS is not going to be an option... I'll just find another solution in possibly Auslogics once again. Much appreciated.