please explain this..? (wireless issue)

Every once in a while, my G5 at work will do some weird quirky things with the wireless network here (like I'll go to join a network and it'll tell me "there was an error joining this network," seemingly for no reason). Have you tried manually typing in the name of the network to see if you can connect that way? Hit "Other..." and type in the name of the network, see if it connects.

Just in case, you've tried rebooting...right? Also, make sure that the antenna-cable going to the AE card is firmly plugged in, all the way. Sometimes that will cause strange problems like that.

 

In the same way that a 2.4GHz cordless telephone interferes with a 2.4GHz wireless router, two 2.4GHz wireless routers in close proximity (aka in the same house) creating two seperate networks will create interfere with the transmission of each other's signal. So while one computer may be picking up that one router, the other computer's connection to the other router could be keeping it from detecting the other one, or something similar.

Honestly my suggestion would be that if you can't use the second router as a repeater for the first one and you can't place your two routers far enough apart that they are outside of each other's range you might as well just turn one off because they will be continuously causing each other troubles.

My dad recently bought 2 2.4GHz cordless phones for his house and now whenever they get a phone call their computers are disconnected from the network until the call is over. I have a 900MHz phone for my apartment so I don't have a similar problem. You just have to be careful with wireless devices because some geniuses decided to make a bunch of the more popular ones share frequencies.