Hey again, matcrz,
Okay, have you tried resetting your iPod? Hold the "Menu" and center buttons together for about 7 seconds before letting off; this restarts your iPod (won't delete any music off of it).
Also, if this doesn't suceed, have you considered a restore?
To restore, follow these steps:
1 - Connect your iPod to your computer.
2 - In iTunes, click on your iPod in the left-source panel.
3 - Under the "Summary" tab (near the top), you should see a "Restore" button in the right-area of iTunes. Click "Restore", and proceed to do so (note that this will delete all the content off your iPod).
Also, this may be your iPod's firmware problem. Have you tried reinstalling your iPod's firmware? For the details on doing that, read this Support article ->
"Firmware file was corrupt" - reinstalling your iPod's firmware
-Kylene
If any post helps or solves your issue, please mark it that way accordingly. Thank you for helping the boards!