Mazen Ahmed has a thorough post up to help you identify and pinpoint issues with the OpsMgr 2007 agent deployment.
While deploying the SCOM 2007 Agent any install/uninstall/repair/update failures are logged in Operations Manager eventlog with Event ID’s starting with 106xx. The 106xx Events are not collected by default..
The basic steps are:
- Create an Event Collection Rule
- Compare the error code to the error code list: http://technet.microsoft.com/en-us/library/ff358634.aspx
Mazen goes into complete detail and steps here: SCOM 2007 Troubleshooting Agents Deployment