Each time when I’ve visited my parents the last five times, I never got a WLAN connection working with my Macbook on OS X 10.5. That’s really bothersome when you are connected to a cable in a small room. Today I had some time to check why it only happens with my Macbook and not with any other computer with Windows installed.
I found a helpful blog post which helped me a lot to solve the issue. As you can see the timeout problem was introduced with the upgrade to OS X 10.5.2. As the solution you simply have to update the firmware of the router. That’s all! Thanks for the nice hint.