"Unable to open ToolTalk channel"

If you open an X window on a remote system and want to run an Xwindows app from there and see the display back on your desktop, the first thing you normally do is play with 'xhost' on your desktop and the value of the $DISPLAY variable in the remote X window:

xhost +remotemachine
DISPLAY=mydesk:0.0; export DISPLAY

    The 'xhost' command is run on your local desktop, and the
    DISPLAY setting is done in the X window on the remote system.

If the app is a little smarter than the average bear, you may get this error when you try to start it up:

Unable to open ToolTalk channel

Here's how to work around the error:

/usr/dt/bin/ttsession -s -d machine:0.0 -c command
In this example, machine would be your desktop (not the remote machine you're executing the ttsession command on) and command is the X application you're trying to run on the remote system.