Some customers have reported issues with the HPC Job Scheduler's event logs after installing Service Pack 1 for the HPC Pack. After some internal investigation, it looks like there is an issue with the SP1 Patch Installer which fails to correctly update the event log manifests (making it so you don't see events in the Event Viewer).
We are working on a patch for this issue. In the meantime, you can manually update the manifest as follows:
That's it! This workaround should restore event log functionality. We are hard at work on a patch that will make this workaround obsolete.
UPDATE: We've managed to fix our patch installer to correct this problem. Installing any post-SP1 patch (for example, this one: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=9d76e266-92d1-49b0-8bf3-cd811b6a5a4c) to the HPC Pack should fix this issue if you encounter it.