New router has a glitch?

In March, 2005, my Linksys BEFW11S4 router died; after 3.5 years of
24x7 use, the radio (WiFi) stopped working. So, I replaced it with
a Linksys WRT54G (running in 802.11b mode). Everything works with
the new router, just as it did with the old router, with one curious
exception: the Link Test (part of CMTOS, Toshiba's W2K client manager
for the laptop's WiFi card) totally fails -- it sees no connection and
gets zero returned packets for the packets it sends to the router
(at a 4 per second rate).

The Link Test has the correct MAC addresses for laptop and for (the
WiFi piece of) the router. The Site Monitor (another piece of CMTOS)
sees the router, on the correct channel, in Infrastructure mode.
The laptop can PING the router and all of the wired desktop PCs, and
the router and the desktops can PING the laptop. The laptop can go
through the router to get to the web, and FTP downloads are nearly as
fast as with the old router. The laptop shares files and printers
with the desktop PCs, just as before. DHCP works, for both wired and
wireless stuff. Changing the channel from 6 to 1 or 11 had no effect.
Turning WEP off and on had no effect. Enabling RTS/CTS did nothing.
Dropping transmit speeds from 11 Mb/s to 1 Mb/s did nothing. Disabling
Wireless MAC filtering had no effect. The Advanced Wireless Settings
are all at default settings, and I'm broadcasting the SSID.

I'm at a loss. Has anybody ever seen this problem? Understand the
problem? Have a fix?
--
Thanks & Cheers, Bob