I imagine you've got this problem all squared away by now; for the sake of anyone who's still having this problem, here's what tech support had me do:
1) Update to the latest version of the firmware.
2) Go to
http://192.168.2.1/ (that's the router's homepage).
3) Click on "Channel and SSID" in the left menu bar (or "SSID" in the "Features" table).
4) Change your wireless channel (arbitrarily, methinks--I was reassigned to 6).
5) Change your wireless mode to 54G-Only.
6) Disable Protected Mode and Turbo Mode.
That's all! I've been fine since then, but it's hard to tell when a problem like this has really gone away.
--R.