Tivo & Wireless Router Still Not Connecting

Can anyone help me?

I have been having trying to connect my Tivo using the wireless network adapter. When I am setting up the network, it finds my wireless router without a problem, however when it tries to configure there is always a "failed while configuring" prompt. When looking at the info for the failed attempt it states a N18 error has occurred.

I have already disabled my router's firewall and tried to reconnect but the same result occurred.

I have an ASUS RT-N11. Does anyone know what steps I might take to fix the connection problem?

Thanks:)