"tkdiff" has been the most useful text file comparison application software.
However, from time to time, the application works or fails to work.
The error message I am getting everytime when it does not work is as follows:

==========================
No protocol specified
Error in startup script: No protocol specified
while executing
"close $pipe"
(procedure "get_gtk_params" line 36)
invoked from within
"get_gtk_params"
(procedure "main" line 27)
invoked from within
"main"
(file "/usr/bin/tkdiff" line 13060)
============================

What is going on with get_gtk_params?

Thanks in advance.