I myself got this same error while playing for the first time this mod. I had already built the Comms, and 3 years ingame ever since, i got to trade with very few ships. When i decided to mess a little bit with the modlist, I realized that the mod will conflict not only with modded storytellers, but also with mods that change the vanilla quests and events.

I was already playing with Randy Random, so it could not be it, then i remembered that i had installed plenty of event mods. My solution was to change the load order of the mods, dragging the More Trade Ships all the way to the bottom of the load list. Ever since I did that, the mod works perfectly for me.