Failed to execute default Web Browser

[ghardin]

I installed XAMPP 32bit version  5.6.23-0 in Linux Lite version 3.8.  Install went without a problem but whenever I click any of the control panel links to go to the XAMPP dashboard or to Apache Friends, it gives a dialog box that says "Failed to execute default Web Browser" "input/output error."
I ONLY have Firefox 72.0.2 installed, but the same error occurs no matter what browser is installed.  I have search for "Failed to execute default Web Browser" and can find no solutions that work.  Any ideas?