TF52001: The name of the Team Foundation data-tier server in the Web Services web.config file is {0}, which matches the new ...

TF52001: The name of the Team Foundation data-tier server 
in the Web Services web.config file is {0}, which matches the new name 
for the Team Foundation data-tier server ({1}).

Verify that you specified the correct names when running the TfsConfig
RegisterDb command, and check to make sure you have not already renamed 
the Team Foundation data-tier server. If you specified the correct names 
and you have not already renamed the Team Foundation data-tier server, 
you must update the Web Services web.config connectionString value with 
the previous name of the Team Foundation data-tier server before running 
the RegisterDb command.

For more information, see "RegisterDb Command" and "Services Web.Config 
File Settings in Team Foundation Server Components" in Help.