That is an actual HBD error, and should be reported to the
correct place.
Edit: comparing your version of HereBeDragons-1.0 (1.13) to the latest version (1.17), I suggest you update your local copy of HereBeDragons first.
Curse:
https://mods.curse.com/addons/wow/herebedragons
Edit #2: I'm guessing your GatherMate2 is outdated as well. I checked Wowinterface (1.38.1 November 20, 2016) and Curse (1.39 January 31, 2017) and you ought to run the
Curse App to get the latest version of that, which will in turn update HereBeDragons for you.
If you are still using the Curse Client v5 (or use a Mac) uninstall it, and install the new Curse App instead.