The Troubleshooting Guide for SCVMM is live a http://go.microsoft.com/fwlink/?LinkId=83589
Here are some general troubleshooting tips:
For any host whose Status property is 'Not Responding,' find the source of the error using the Jobs view. Open the Jobs view, select a job, and click on the Change Tracking tab in the details pane. Then navigate down the jobs until you find a host job where the Status property changed from 'Responding' to 'Not Responding'. Once you find this job, click on the Summary tab of the details pane to understand why your host is marked as Not Responding.
For any error involving online conversion of a physical server (P2V) and the Volume Shadow Copy Service (also called Volume Snapshot Service or VSS), first determine the VSS provider reponsible by scanning the application and system event logs on the source machine. Try to fix the issue indicated (such as not enoung disk space). Then, try restarting the service associated with the VSS writer failure message, and then try the convert physical server wizard again.
For any error that occurs after installation, isolate group policy as a possible factor by moving the virtual machine to its own organizational unit in Active Directory with a block on inherited policy, and trying to reproduce the problem. If you cannot reproduce the problem, it is likely that a group policy setting is a contributing cause.
For general database connection errors to a remote SQL server, check that the remote SQL server is running under an account other than Local System. If that is not the issue, check that the Service Principal Name (SPN) was created for the SQL service according to the instructions at http://go.microsoft.com/fwlink/?LinkId=88057. For further instructions on setting up a remote SQL Server 2005 database, see Configuring a Remote Instance of SQL Server for Virtual Machine Manager at http://go.microsoft.com/fwlink/?LinkId=87356.
If you are unable to open the Virtual Server Administration web site with an "Access denied" error after Virtual Machine Manger installation, it is likely because the enhanced security settings in Windows XP SP2 and in Windows Server 2003 SP1 prevent access to the Virtual Server Administration Web site. You must have sufficient DCOM permissions before you can use the Virtual Server Administration Web site to connect to Virtual Server 2005. For more information, see the KB article at http://go.microsoft.com/fwlink/?LinkId=87304.