I'm trying to connect my printer (HP Photosmart 2710)to my wireless network via my new Netgear Gateway 7550. The printer will not accept the Wireless Network Key for the router. Had no problem with the old 2Wire gateway.
That raises the very likely possibility that the printer is expecting WEP/WPA, but your new router is configured for WPA2. If that's true, then you have to either use a wired network connection, or else use WPA on the router. Some routers will have an option that supports both at the same time, so that might be a solution as well.
P.S. I checked that guide a little more closely and found this (pg., 36):