One assumes the PC is ON at 10:59 every Tuesday. It will only scan at the scheduled time so if you boot up just after or any time before the next schudule, it won't run. If you have tested the config by setting it to scan and then waiting for it, and it doesn't, then it has to be it's configuration or a problem with the installation. If you are certain the config is correct, try un-installing and re-installing it again.
Mine is set to run daily at 12:00 and it kicks in exactly on time.