Our previous router died, and to replace it I procured an apple airport extreme. My mac, my wrt54gs (with ddwrt acting as a bridge) and a linux machine have had no problem connecting to the wireless. None of the wired clients are having a problem obviously.

The problem is one of my roommates can not connect. That's not strictly true. He can connect to the network, and will, infact, get a dhcp lease. However he cannot get any packets out. Can't ping the router, can't access any web sites, nothing.

However he's fine if we switch to an unsecured network. Which is obviously not acceptable.

The airport only allows for 'wpa/wpa2 personal' and 'wpa2 personal' (and of course the enterprise versions there of)

I keep reading about this problem in multiple spots on the web, but never see any actual answers...

Anyway the laptop:
hp/compaq cq50-215nr
vista home premium
wireess card: atheros 5007

airport is simultaneos dualband II