Restoring my ipod 30 gb classic

Hi, i've recently gotten an ipod classic 30Gb from someone else. I did not buy it. Anywho, I tried to restore my ipod to the factory settings and it told me to plug it up to a wall charger. I Plugged it up to a thrid party wall charger and the meassage displayed on the ipod is will not go away. It shows the old HUGE wall chargers that originally came with the ipod. I do not have one because i did not get one when i got my ipod. Is there anyway to make this go away and go back to listening to music? Please help!