Well, there's more than one way to approach a problem.
Ummm, I think the first thing I'd do is 1) check the altiris logs for any indication of WHY it's timing out. Deadlocks for instance? 2) I'd check SQL for any indication there of what might be happening. Maybe SQL is just overworked.
3) failing that, I'd edit the report directly via XML so that I can make it fail, and then get in and fix it. :P If you right-click the report (not left click) and export the XML, you can then modify the SQL to do something really really simple, comment out the rest of the code but leave it in-tact, re-import it, then edit it when it succeeds.