I wanted to post about a problem and solution for a problem I had....
I have a laptop with vista and a desktop with 7. I use synctoy to sync files between the two, but ran into a problem. There is an external HD on the desktop with media files on it, which I just added via the library function rather than copying onto the local HD on the desktop. I could not access the My Pictures/Music/Videos folders by maping the network drive nor by directly enabling file sharing. I tried fixing owners, advanced sharing options etc etc... nothing worked.
The solution? I had to go to the 'Libraries' folder and then enable sharing from there, for each (my pictures/videos/music), by share with / add 'everyone' and select 'read/write'.
Just fyi...