If anyone is having difficulty using the Airlink AP411W with Linksys WRT54G, I have the answer. The SSID must NOT be blocked. This will end your chances of ever getting it to work. It's poorly documented. But works fins.
I have the Airlink in the Client mode for my Solaris system. It works fine, and all in the same subnet. Your gateway and name server stuff goes in the client computer and the Airlink acts only as a wireless to LAN converter.