What does /etc/resolv.conf contain when you get a connection in Mandriva? The fact that you can connect, but not get on line seems odd.

On the subject of you having a fondness for Kubuntu that's quite understandable and I'm not trying to convert you, just trying something that I know should work.

You might be best of trying on Kubuntu forums if no-one else here can help. I don't know enough about Kubuntu to advise and have never had to dabble much in command line tools for WiFi.

Again, I would advise you speak to your sys admin.