gtkpod permissions problem

[Rem P Roberti]

I have installed gtkpod for use with my Nano, but I'm having a problem
when trying to add files.  The Nano is mounted at /mnt/ipod, and when I
try to add a file I get a message similar to this:

Transfer of 'Petite Fleur' failed. Error opening
'/mnt/ipod/iPod_Control/Music/F00/gtkpod795096.mp3' for writing
(Permission denied).

The file, in this case Petite Fleur, shows up in gtkpod, but it can't be
written to the Nano.  This obviously looks like a permissions problem,
but I can't figure out its cause.  

TIA,

---Rem