When running installers on recent SVNs it often warns that certain files are locked. If you leave it for 20 seconds the file will no longer be locked (is locked by tvservice.exe in the meantime even though installer says service has ended)

h4. Additional Information
See discussion in internal thread. Looks like SVN 26590 made tvservice.exe start/stop asynchronous and installer is only waiting for service to confirm it is ending not that it has actually ended.