It does use the port tcp/7801. Seems like the NSM processes are down. Can you verify using
/usr/netscreen/GuiSvr/bin/guiSvr.sh status
If the guiSvrManager process is down, can you try to restart the processes using
/usr/netscreen/GuiSvr/bin/guiSvr.sh restart.
If that doesn't work, then provide us the details for the /usr/netscreen/GuiSvr/var/errorLog/guiDaemon.0.
Thanks,
Chandra