The full error is:
Failed to check out the file. The service "Microsoft.VisualStudio.Shell.Interop.IVsRunningDocumentTable" must be installed for the operation to succeed. Ensure that this service is available. Check the source control server status and try again.
Don't know what to tell you about this one other than I was getting it today when trying to load and update a VS2003 web service in VS2005. The load/update tried to duplicate a dataset as part of the reference.map as close as I could tell. I deleted the duplicate DS file and found that the web service load/update still worked, in spite of the error.
I did have the web service open in a VS2003 project at the time and was making changes to it. After closing both '03 and'05 sessions I was able to load and update without an error. Very little available online about it, so I am letting this one ride.
