HELP, DOCK CHARGER

[Fender83]

i recently traded my psp for this 3g 30gb ipod with dock it says you can charge it from the dock but when ever i plug it into the computer it shows a pic of a battery with low juice and a yield sign, can anybody help me?

[mad jew]

Please:

Just make one thread (http://forums.macrumors.com/showthread.php?t=137818).
Don't use only capitals in your title.

Thankyou. :)