Today at a client, we stumbled upon a problem when updating MOSS2007 SP2 with .Net Framework 3.5 SP1. Everything seemed to work fine, but Search & indexing was not working anymore. The error log showed the following: EventID 6482 - Application Server Administration job failed for service instance Microsoft.Office.Server.Search.Administration. SearchServiceInstance
Indexing and serving search queries is handled by diffetent servers in the clients environment.

After a bit of googling and bingging we foud this exelent post by Andera Glaser that decribes the problem and the solution to the problem.

http://andreasglaser.net/post/2009/09/13/SharePoint-2007-and-EventID-6482-Application-Server-Administration-job-failed-for-service-instance-MicrosoftOfficeServerSearchAdministrationSearchServiceInstance.aspx

More info about how to fix the problem:

http://support.microsoft.com/kb/962928