Your network might be using the 802.11g protocol, and the RC9800i is only 802.11b compatible. Try and see if you can find the wifi mode in the router setup, and use the mixed b and g mode.

Otherwise, try to setup the RC9800i network from the beginning, and make sure that the IP address is correct, as it might change from one router to another (DLink routers are 192.168.0.1 and lynksys' 192.168.1.1 for example), or maybe DHCP is not activated on your new router.

Or it might be a firewall problem.

Hope this helps. I'm not am expert though.

Bragon