G4 Airport connection issue

Hello,
I had been connecting to my landlord's network via Airport (G4 Quicksilver, OS X 10.4.11). He recently obtained a new wireless service, and I now am unable to connect. The name of the network appears, but I receive the following error:

There was an error joining the AirPort network "XXX".

I have tried all of the WP options, and have verified the password (I can connect with my laptop).

Any thoughts?

Thanks!