Can't get to configuration page on my access point

I am running a whole-house ethernet wiring set-up with a cable modem and wired-only router in my central wiring panel. The router has an IP of 192.168.1.1 and allocates LAN IPs from 192.168.1.100 through 150. I am trying to add a Buffalo Airstation router to use a wireless access point. The Buffalo router has an external switch that allows it to run as a router, as "auto" meaning it senses whether there's another router, or off, which puts it in bridge or access point mode.

I hooked the Buffalo up to my network using one of its LAN ports and plugged the other end into a switch, in other words, not connected directly to a modem or computer. I powered on in Router Off mode, but it never got assigned an IP from my router. I rebooted in Auto mode, and my router assigned it the next IP available, which is 192.168.1.103. So, I wanted to access the Buffalo configuration page. I went to 192.168.1.103 in IE on one of my PCs, but nothing loaded in the browser. The default IP for configuration of 192.168.11.1 seems irrelevant when used as an access point.

How can I access the configuration page? I can reach the main router's page at 192.168.1.1, so why the *** can't I access the Buffalo configuration page at 192.168.1.103?? I've tried in both auto and off mode after getting the IP assigned, and nothing works.

Please help.. very frustrating.

Thanks,
Brian