When I startup my computer, all of the active wireless networks (I'm in a large apartment building, so there are several, including my own) show up nicely in my airport menu. I can pick one, and it works fine. Then, if I try to change the network I am using, I get an error and then all of the networks disappear from the menu. The only way to get them to reappear is to restart. I am using a TiBook 500 with 10.3.5. I'm not sure where I should check for what version airport software I am using, but Admin Utility is version 3.4. This problem has occurred when my network is coming from a linksys wireless-B router with 4 port switch and when it is coming from a dual ethernet (snow) ABS.