Mandriva 2008 immediately switches back to WEP instead of WPA

[H4N5]

I have recently installed Mandriva 2008. It identifies my wifi-adaptor correctly, and it shows my wireless network in the list.
I don't manage to get a connection, though. The network uses WPA. I tried to configure Mandriva to use WPA, but when I reopen the configure window, after closing it with the OK-button, it says WEP again.

I installed the windows driver with ndiswrapper instead of de linux driver. I followed the steps in this tutorial: How to get Ndiswrapper with wpa_supplicant working - LinuxQuestions.org
With the step

wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -Dwext -w

It failed. A lot of "opperation not supported" errors and some other text.
I don't know how to fix it. Please help me!

[waterhead]

Try just using the Network Manager GUI. I don't know what it may be called in Mandriva, but it is a frontend for network manager.

[H4N5]

Try just using the Network Manager GUI. I don't know what it may be called in Mandriva, but it is a frontend for network manager.

That was the first thing I tried, but like I said it switches back to WEP when I set it to WPA when I close and reopen the window.