alright I have read your routers manual. (yes I'm a nerd)
term confusion between routers, or just me brain.
Use shared key. not auto.
If you are using the same WEP key on both ends I don't see why it is not working. unless the driver is a no go.
to be on the safe side (like me) change the essid from the default and dont broadcast it.
this will mean that you will have to enter it on the linux end and stops confusion if there are any other of the same wireless routers in the area.
Yes I have seen this type of confusion and even though the router to be used was closer the system would not connect.
hope this helps.