I upgraded to SP2 MP1 recently and noticed a day or two later that no clients were updating. I'v been wrangling with Altiris for a few years now and thought "Ok, lets go through the standard motions" here is what I have done so far (pulled from my active case with support)...
Attempted most common repair steps to resolve failure of NSE processing:
1. Cleared NSE and restarted services
2. Repaired SMP
3. Cleared NSE and truncated resourcemerge table on DB
4. Checked database for deadlock and performance issues
5. Truncated Eventqueue table and Eventqueuestatus table (Rebooted everything after this)
6. Moved event processing to another folder on server using sym doc.
7. Moved event processing to another NS server
(At this point I became very suspicious of the DB)
8. Paused NSE receiving with the configurator application to see if nse would process, no movement after 1 hour of paused flow
9. Followed this document… again
http://www.symantec.com/business/support/index?page=content&id=TECH183347
I'm very stuck, anyone have anything else to try?