In terms of the Text package, that is stored in a zip file with the extension
.sublime-package. It should be in a folder named
Packages/ that is a sibling of the sublime_merge binary.
Do you have Sublime Text installed on your machine? It may be an interaction between Sublime Merge and Sublime Text. To test this, you could follow the directions at https://www.sublimetext.com/docs/3/revert.html to move your Data folder for Sublime Text and see if that helps Merge launch properly.
Alternatively, perhaps something is blocking access on your machine? What platform are you on?