I think I may be having the same problem. My computer connected fine, then I updated all the software, and it worked fine for a little bit. but, one day i came home and it can't connect anymore. It says "there was an error joining the AirPort network", but my PC and 4 other PCs on the network connect fine. I take my pbook to school and work and it connects fine there. I run the network diagnostic utility, and it says my home network needs a password, but there is no password encryption turned on, and none of the PCs need a password to connect. what's going on??