You can run them manually if they no longer run automatically. You may be able to fix the problem with the following command, but you may lose your rules in the process.
Here’s another method from techyforums.com…
If your rules have stopped working or are working inconsistently then it could me due to a corruption in your data file. Luckily there are a couple of built in tools that should be able to fix this problem.
Browse to C:\Program Files\Common Files\System\MSMAPI\1033 and there should be to exe’s:
Close down Outlook and make sure that any Outlook processes are also closed then put the above exe’s one at a time.