Comment 89 for bug 259278

This was probably already mentioned earlier, but what I have noticed is that my wireless works just fine with DHCP and WEP/WPA networks, but if the nm-applet (which is called network-manager-gnome in Ubuntu) is installed knetworkmanager doesn't work, but nm-applet does. If uninstalling nm-applet doesn't fix your problem, reinstall it and use it instead of knetworkmanager for now. I have found it generally better at supporting the NetworkManager core. I'm sure this will be fixed though, but probably for the next release of Ubuntu.