Backup My Documents on Client Machine (robocopy and xcopy access denied)

I have roaming profiles set up on our network.  One day a user logged in and all of his files were gone (including the ones on the server).  Also, unbeknownced to me his roaming profile was not getting backed up.  

My guess is the GPO saw a blank folder and just wiped all his files.

Needless to say, I'd like a local copy of all files on peoples machines (one hidden away from GPO).  I'm trying to copy the "%userprofile%\my documents" folder to "%userprofile%\backup\docs" folder.  

I keep getting access denied.  I can do this with the desktop and the favorites but not the my documents folder.  Any ideas how to keep these backed up on disk somewhere (locally)?

Thanks,
JOe K.