beefy,
install fun_plug, install then activate telnet. (http://wiki.dns323.info/howto:fun_plug)
install a small software called Putty.
Use Putty to telnet your box.
when you have telnet access you can navigate your box from its OS (linux),
"ls" will show you the files/folder in the actual folder you are in
"cd" will allow you to go to a folder, "cd mnt" for example, then cd HD_xx, cd your folder (Case sensitive!)
hitting TAB key will complete the name of the file/folder you're typing, if you have a folder called azerty, type cd aze then push TAB, it will complete the name.
you will find your disks in /mnt, with names like HD_a1, HD_b1
spot your files and remember their path (with ls and cd)
then you can move file using "mv", like this:
mv /mnt/HD_xx/your folder(/your file) /mnt/HD_xx/your folder/
voilą! I hope it's understandable
Let me know!