I get this error when I try to load a VS 2008 project from TFS source control:
The project file has been moved, renamed or is not on your computer
Clear out your workspace mappings (File -> Source Control -> Workspaces). Edit the workspace and either clear out all the mappings (more repercussion) or find the one that's associated to this server path. Then open Source Control Explorer and remap. Double click the SLN in Source Control explorer and it should get latest. Not entirely sure what has happened or what state you managed to get into, but with this should get you moving again.