Hi there,
In addition to killing NetworkManager and the deamon, and restarting them you might try to just bypass NetworkManager all together and just use iwconfig to set up the connect.
iwconfig - Wireless Interface configuration utility in Linux | SUSE & openSUSE
The idea is just to see if you can get it working at all, then play with the GUI more. But if you can at least get it working with the command line then you know the kernel module is working, etc.
I tend to think that the Mandriva worked with due to a different kernel module for the wifi, or a different version of NetworkManager, etc. It's not so much the kernel itself, but rather the kernel modules for wifi: #lsmod will list all your currently loaded modules.
Oh, after you get a connection with the access point you will likely need to run dhclient to get a DHCP ip address - other wise you will need to set that manually as well.
Cheers,
Pete