Okay, so just so people are sure that they have the same problem I did, I'm giving a little background on my problem -
I have an iPod mini and I've had it for 2 and a half years now. About a couple of months ago, it would just stop midway through a song and say something like 'low battery, please re-charge' even though, there was more than enough battery time left. So I would go home, stick it into the charger and as long as it was in the charger, it worked just fine. Then as soon as I took it off, within a minute into hitting play, I would get the same error message again. I even went so far so as to charge it undisturbed for two days and nothing worked.
So after calling Apple and finding out I'd need to pay $77 just to get a new battery (!!!) and was considering getting a new one, I decided to do one last thing and try putting the iPod into disk mode. As soon as I put it in disk mode, I reset it... and it's been 3 days now and I haven't gotten that error message since.
See link below for how to put your iPod into disk mode:
http://docs.info.apple.com/article.html?artnum=93651
Hope this helps.