I have been wrestling with a network problem for a day or so and I hoping that sharper minds than mine will be able to help!

For the past couple of years my setup has been as follows:
Two Philips Series 1 units, Turbonet/Terbonet cards in each, one running the 1.6 image and the other the 1.5 image. The Tivos together with an xBox1 are connected to a switch which is connected to a Linksys WET54G wireless bridge. The bridge communicates to a Netcomm N5WPlus4W modem/router which has both wired & wireless clients using static IP addresses on the LAN side. The wireless network uses WPA security with a shared key.
This has worked very well ever since I set it up.

Recently I have upgraded the router (to take advantage of VOIP) to a Billion 7401VGP R3 router. Everything seemed to be OK... the computers on the network all working, VOIP working etc until I discovered the Tivos were failing to make the daily calls. On checking I found that I had forgotten to change the gateway from the Netcomm's 192.168.1.1 to the Billion's 192.168.1.254. To my surprise I still could not get the Tivos or the xBox to connect to the outside world.

I tried bypassing the Wireless Bridge and that worked. I was able to make the calls.
My problem now is 'why won't the Bridge work as it did before'?

With the Bridge connected, I carried out the network checks and from either Tivo I can ping any IP address on the LAN side except the router gateway.

The gateway for all LAN clients including the Tivos, xBox and Bridge is the router's IP address.
I can ping this address from any of the computers wired or wireless on the LAN........just not from the Tivos or xBox via the Bridge.

I would be grateful for any comments or ideas!