Any time the game cues up a trade caravan from any of these factions: I get this error message and they don't show up:

Faction Coastal Townsfolk of Black Lagoon of def ROM_Townsfolk has no usable PawnGroupMakers for parms groupKind=Trader, tile=90810, inhabitants=False, points=906, faction=Coastal Townsfolk of Black Lagoon, traderKind=Caravan_Outlander_Exotic, generateFightersOnly=False, dontUseSingleUseRocketLaunchers=False, raidStrategy=, forceOneIncap=False, seed=
Verse.Log:Error(String, Boolean)
RimWorld.<GeneratePawns>d__1:MoveNext()
System.Linq.Enumerable:Count(IEnumerable`1)
JecsTools.HarmonyPatches:GeneratePawns(PawnGroupMakerParms, Boolean, IEnumerable`1&)
RimWorld.PawnGroupMakerUtility:DMD<DMD<GeneratePawns_Patch2>?-506290048::GeneratePawns_Patch2>(PawnGroupMakerParms, Boolean)
RimWorld.IncidentWorker_NeutralGroup:SpawnPawns(IncidentParms)
RimWorld.IncidentWorker_TraderCaravanArrival:TryExecuteWorker(IncidentParms)
RimWorld.IncidentWorker:DMD<DMD<TryExecute_Patch1>?-576406144::TryExecute_Patch1>(IncidentWorker, IncidentParms)
Verse.<>c__DisplayClass6_1:<DoIncidentDebugAction>b__2()
Verse.Dialog_DebugOptionLister:DebugAction(String, Action)
Verse.Dialog_DebugOptionListLister:DoListingItems()
Verse.Dialog_OptionLister:DoWindowContents(Rect)
Verse.Window:InnerWindowOnGUI(Int32)
UnityEngine.GUI:CallWindowDelegate(WindowFunction, Int32, Int32, GUISkin, Int32, Single, Single, GUIStyle)


Any idea what might be causing this?