Error 1456 when running via Firefox on Ubuntu

[BobUnitt]

I'm trying to use UltraVNC from Firefox 2.0.0.6 on Ubuntu-Edgy to access a local-network-connected Windows-2000 desktop. I've successfully linked using UltraVNC from Firefox on another W2000 workstation in the same network, so I'm fairly confident that the server-end of the link is OK.

I'm accessing via 'http://[dotted-quad]:5800/' and getting a 'VNC Authentication Screen', to which I enter a W2000 user-name (no password), but when I press 'OK' I just get a glimpse of part of the target screen, after which the screen goes grey and displays the message 'Error 1456'.

[redge]

logon username authentication apply only for windows, otherwise fail.

[redge]

i forget, the work around is to uncheck the mslogon, so you have only vnc password authentication.