Periodically lose wifi connection using NetworkManager

I have a Fedora 8 box, with NetworkManager 0.7.0. After some messing
about with fwcutter to get my broadcom chipset working, everything is
fine. Except that periodically the WiFi connection drops, the network
manager applet spins for a few seconds, and the NetworkManager
reconnects. This happens every so often, sometimes as often as a
couple times an hour, usually every couple hours. This is happening
when the box is connected to a BuffaloTech WRT54g, but I haven't tried
connecting to other access points.

Any ideas what might be causing this or where i should look? Here's
an excerpt from wpa_supplicant.log


CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
Associated with 00:07:40:a2:45:bc
CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
Associated with 00:07:40:a2:45:bc
CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
Associated with 00:07:40:a2:45:bc
CTRL-EVENT-DISCONNECTED - Disconnect event - remove keys
Trying to associate with 00:07:40:a2:45:bc (SSID='930s18th_Local'
freq=2457 MHz)
Associated with 00:07:40:a2:45:bc
WPA: Key negotiation completed with 00:07:40:a2:45:bc [PTK=TKIP
GTK=TKIP]
CTRL-EVENT-CONNECTED - Connection to 00:07:40:a2:45:bc completed
(reauth) [id=0 id_str=]

No timestamps, but I see quite a few of these and the time on the file
corresponds to the last drop.