Not all music Updating

[NING]

So all of a sudden none of my purchased music will update to my ipod. Three people have used my library in the past. Does this have something to do with it. Please help as I spent a lot of money and want to hear my songs!

[mad jew]

Two articles form Apple you may be interested in:

1. Purchased music won't play in iTunes. (http://docs.info.apple.com/article.html?artnum=93035)

2. Songs won't copy across to iPod. (http://docs.info.apple.com/article.html?artnum=93867)

I'm not sure how useful they'll be, but hopefully they'll help. :)