I tried following the process described in this article: http://blogs.technet.com/b/sbs/archive/2009/04/16/how-to-backup-restore-and-re-link-group-policies-in-sbs-2008.aspx
When I followed these steps I had over 50 paragraphs of output similar to this:
GPO: Update Services Client Computers Policy...Succeeded, but note the following issues:
[Warning] The security principal [S-1-5-21-4187703203-36778
6] referenced in extension [Core Extension] cannot be resolved, but the task will continue. In the future, you can use a migration table to map or remove this security principal.
Details: No mapping between account names and security IDs was done.
What does this really mean and what concerns do I have with so many warnings?