I can't connect to the router

I have an ASUS WL-520G, and an ASUS WL-138G V2 wireless network card. All drivers is installed. The network card can see the wireless network, but it won't connect to it. It is an open system network without wep encryption. When I click on the survey page on connect button my computer works for a while and nothing happens. I've turned off firewalls.
I have another computer it connects the wireless network.

On Status&log -> wireless page I can read this:

Mode : AP Only
Channel : 1

Stations List
----------------------------------------
00:17:31:21:0C:12
00:15:F2:A0:DE:E4 associated


The first id is the computer which won't connect to the network.

What can I do?


Thank you.