I didn't notice the 'ff or fr' bit before.
The DMS hack tools doesn't re-index things very well (compared to PhatHack Media Manager) so the box is properly seeing your DMS files as corrupt.
To fix that, use your favourite software to remove the 1st playlist (inserted by the DMS hack tools, that is used to run the hack) and save/eject as normal and you should be back up and running again.