[X4U] Can't Join Airport Network

[Lawrence Haber]

I would appreciate some help with my 700mHz 15" G4 iMac.

Whenever I attempt to join an airport network I get an error message  
"There was an error in join the Airport network "name of network".  I  
get the option to either "Try again" or "OK", but no success in  
trying again.

I have thrown away my airport preferences countless times.  And now  
for some specifics:  this model uses the original type of Airport  
card.  the machine does see the card both from within the System  
Profiler and from within Internet Connection.  I can "see" the  
networks out there and can attempt to join, I just can't join.

And not for the truly weird: thinking that there was something really  
strange and messed up, I reinstalled the OS (10.4 and 10.3) and  
during the initial phase after re-installation of the OS, the airport  
connection worked fine and I was able to download lots of updates.   
And, during several restart sequences, the airport connection  
continued to work just fine.  But after a nice long sleep overnight,  
upon reawakening the airport can no longer connect.  This occurred  
twice since I attempted to reinstall the OS twice, once to 10.4 and  
most recently to 10.3

The inability to connect does not impact two other machines and  
whether it is my WEP protected network, or my neighbors open network,  
doesn't make a difference.

I would appreciate whatever suggestions you all might have