I suppose, this is not supported, but it's interesting: One User has a MacBook Pro 15" Retina, Bootcamp and Win7 x64 Pro on it. NC2 SP3 IR5 is installed.
Because this is a Notebook, he logs only in to the desktop. After the desktop is loaded, he wants to log in to Novell via the red N in the systray. Almost everytime he gets the error message "The login interface is already in use. Please complete or close the existing login dialog and then click Retry." - But of course, this is the first attempt to login. No open windows, nothing in the taskbar.

The only workaround is to start the loginw32.exe directly. It doesn't help to kill the process nwtray or reboot.

Does anyone know what's going on?