You may encounter following error when using Spotlight:
Monitored Server - Replication Connection Failure 3/18/2011 1:02:00 PM Cannot connect to Replication instance 'NAME_of_SERVER' : Unable to load assembly: Microsoft.SqlServer.ConnectionInfo
Check to see if the SQL Server Management Tools are either not installed or corrupted.
Note that to use Spotlight on Analysis Services, Spotlight on SQL Server Replication, and Session Trace and SQL Analysis in Spotlight on SQL Server, the SQL Server Management Tools must be installed on the Diagnostic Server (DS). Afterwards, you will nee to restart the Quest Diagnostic Server Service in services on Diagnostic Server machine.