Shailesh,
I am not able to directly contribute understanding of the problem you have posted.
When I posted this original question I was not knowledgeable with the Linux operating system.
My understanding has improved somewhat.
My problem with XCTU was lack of understanding the intended installation process.
I will post the solution I discovered to my installation of XCTU. I hope this may possibly be helpful for you:
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Ubuntu ver 14.04
1) Download the XCTU tar file from Digi.
2) Unzip the tar file. The content is a single file, 40002881_C.run
This executable is the installer.
3) Change the file properties to make the installer executable
4) As root, execute the installer.
5) The installer will ask for an installation directory.
The suggested default location is /opt/Digi.
6) When the installer completes the installation, look for a file XCTU.desktop
This is the desktop file created automatically by the installer.
Move this file to /user/share/applications. (in Ubuntu)
Notice, this application will run (at user level) only when called from this desktop file.
The EXEC instruction calls the XCTU program with required command-line parameters determined upon installation.
There is a suitable icon for desktop included in the installed files, which is referenced with the desktop file.
7) Change the file permissions of both the installation directory and all it's files to user, read/write.

Ensure the XCTU program has access to any serial ports used (the user has entry in the “dialout”).
Reminder: after adding user to the dialout, you must log out and back in.
Notes:
On another install using this procedure, the XCTU program failed to start, posting an error message directing to a log file. The path described for the log file is /home/rick/<a hidden folder>
The log file cited a folder for work files /opt/digi/xctu-ng/workspace.
This folder was not created in the installation process.
The solution was to create the workspace folder manually, set it's permissions to READ-WRITE.