It's not a password it's called Wep code it's a way to protect your router's wi-fi from being stolen by your neighbours. The Nintendo DS accepts only WEP codes there are longer and safer codes than the wep but as you said they won't fit. Go in your router's wi-fi settings and set the key type to WEP.

This post has been edited by Artins90, Mon, July 26th, 2010 at 21:36