Try a hard reset as mentioned in the post above, could help.
From Apple site :
To reset iPod, iPod (Scroll Wheel), and iPod (Touch Wheel)
Connect iPod to the Apple iPod Power Adapter and plug the power adapter into an electrical outlet, or connect iPod to your Mac's built-in FireWire port. Make sure the computer is turned on and isn't set to go to sleep.
Toggle the Hold switch on and off. (Slide it to Hold, then turn it off again.)
Press and hold the Play/Pause and Menu buttons until the Apple/iPod logo appears, about 6 to 10 seconds. You may need to repeat this step.