[Edit]
I understand if there isn't any time for a response, I'm already benefitting from a lot of grace and charity here.
I've removed my previous mercenary_tables.sql and used the provided mercs.sql with no errors, although I still recieve the identical bug (vendors have nothing to sell, but will still buy).
I am using Akkadius' installer package found here (on Windows 10):
http://analytics.akkadius.com/dl/eqe..._files_x64.zip
Vendors work fine if I remove mercenaries entirely.
I want to figure this out before I dip my toes into something like learning to edit LUA scripts or further material. Maybe I shouldn't! haha...