Airport Extreme - "There was an error joining the AirPort network"


"There was an error joining the AirPort network xxxx" when I try to log onto my airport network with my g5 (running tiger). It worked fine until yesterday, it's decided it doesn't want to work anymore.

I restarted my Airport Base station and DSL Modem
I can log onto / use the net with my laptop just fine (how I'm typing this)
I got a new Airport card for my G5 and it didn't work.
I tried to run airport setup assistant and it says there's no airport network setup.
Airport Admin Utility won't show any network

any ideas?
well, I rebooted my base station, the computer saw it and I set up a new network and it seemed to work.

interestingly enough, my old network is still on my networks list, but my computer still won't connect to it.
If you do a hard reset on the base-stations, the passwords are reset to public. Moreover, if you have trouble with a consistent connection, try playing with the channel settings. Had a similar issue with a friend's, we finally got the right channel. I remember the base station complained about wrong password, after a hard reset. The Apple tech told us, it will revert back to public.