Legacy AirPort card can't associate with SonicWALL TZ 170

I have a good old original (not "Extreme" ) AirPort card in a 2001 iBook that has worked flawlessly with every B network I've ever tried to join for the past 5 years. I just upgraded to a SonicWALL after getting a really good deal on a used one from a telecommuter who was fired, and have had nothing but problems with it on the wireless end. Sometimes (rarely) the iBook will join without a hitch, but most of the time it takes over 5 minutes worth of repeated trying to get an association. Looking at the router logs, there are endless streams of these going on within seconds of one another:

4 04/25/2006 14:43:56.352 802.11 Management 00:30:65:13:F4:AD - Fail Association because of too many stations already
5 04/25/2006 14:43:56.352 802.11 Management 00:30:65:13:F4:AD - Authenticated

This makes no sense to me, as

1. I have the number of possible stations left at the default setting of 32

2. The status page shows 0 of those 32 stations in use

3. I only have one wireless station trying to connect

4. MAC filtering is on and allowing ONLY that one station

Nevertheless, the AirPort card cannot get past authentication over 80% of the time.

I have tried disabling every fancy security setting available on the router, and the only thing that seems to have improved my odds of being able to join was lowering the signal strength to "Lowest". I'm perfectly willing to accept the possibility that such an old card might simply be out of spec and doing something improperly, but since it's worked everywhere else I've tried it, I don't see why it would fail here.

Googling that bogus error didn't turn up any results at all, so has anyone ever seen anything like this before anywhere else? I obviously have no support agreement with SonicWALL since I bought it used.

Edit:

Firmware Version: SonicOS Standard 3.1.0.7-77s
ROM Version: SonicROM 2.6.0.0