problems with java viewer NT 4.0

[Guido_Vetere@tivoli.com]

Hi,
I'm trying to start Vnc java viewer on Win NT 4.0 (client & server), but
both the applet and the application block in the autentication dialog.
As for applets concerns, Explorer 4.0 and Netscape Communicator show the
same behaviour. The application was build with Symantec VisualCafe PDE 2.5
(jdk 1.1).
Debugging the app, it seems that it blocks reading the first message.
Note however that the VNC viewer works fine with the same server.
Any hint ?