Vista + 3945abg = Can't find 802.11a?

I have a shiny new Vostro 1500 with the 3945. So far it's been running great on my local .11g network. However, it doesn't seem to see the .11a router at all. I know the a router is working, there are two other Dells (Inspiron 8000 and a fossilized old 4000) that see the .11a network just fine and run on it. I checked in the device manager, and it's set to a/b/g mode, and in Dell Quickset I made sure that the Catcher's set to a/b/g. Is it a problem with the Vista wireless manager? Or is there something else I'm missing? The system has no bluetooth installed, and the driver is 11.1.1.22 dated 8/8/07. Thanks!