Had the same problem, with corrupted files and decided the format the player. The strange thing is MP3 Player Disk Tool (ver 4.18) says on the Format tab:
Capacity 3826.22 MB
Total sectors: 7836097
but on the Partition and Encrypt tab
Disk total capacity 7924MB
Now after the format only get 'Disk Error!' message
Windows format says
Capacity 7.73 GB
but is the same problem 'Disk Error!'
SQEEEK, please, can you explain what you mean with 'set it to only let the 'normal' partition show up'? How do you do that?
I went from having a problematic mp3 player to have a piece of metal

Don't want to dismantle the player, I tried but seems hard and don't want to end with the pieces of my hands if it can be solved by software.
What can I do to fix the problem? Please
Firmware is:
2008/09/05
9.5.54
QS_AK2025
2008/04/23