thanks Petr0id you are Lord, how on earth do you know this stuff?!
i am using Windows 7 64 ultimate on two different machines both virgin installs on brand new drives, and my network share is on winxp pro on a 3rd machine. I have been having htis problem for ages and it was doing my nut in. this morning i decided to rename 70 folders and about 1 in 5 was not renaming due to this error, but it's sunday morning, all my machines were turned off last night and this is the first job i decided to do so there is no way any files were in use by anything.
I followed your instructions as best i could although i DID have a public folder, i made my file called fix.txt and renamed it shiftfix.reg (cos i only just noticed you called it shitfix ha ha ha), ran it and now those 10 or so folders that wouldn't rename all renamend first time, you just made my life better thank you :-)