Changed the add-on in xdrp on the server in precise / 12.04 from tightvncserver to vnc4server, and the problem disappeared. Thus it was tightvncserver causing the error.
** Package changed: rdesktop (Ubuntu) => tightvnc (Ubuntu) ** Summary changed: - lucid tsclient channel_register error on connecting to precise + tightvnc sends bad request causing rdesktop and/or remmina to crash with Unity -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1080006 Title: tightvnc sends bad request causing rdesktop and/or remmina to crash with Unity To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/tightvnc/+bug/1080006/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
