Rated 5 out of 5 stars

Follow the instructions provided by Paul Osborne (https://addons.mozilla.org/de/firefox/addon/launchy/reviews/468944/) (thanks for that), but additionally replace all occurrences of 'gContextMenu.link' with 'gContextMenu.linkURL' in main.js (Line 216, 381 and 421). This will fix the 'Permission denied' error.

It's now working for me with TB 17.0.2.