Severe lag when a caravan appears.

[Eetere]

I was playing just fine, then a caravan that I called in appeared and everything lagged horribly. If someone could tell me how to fix this, I would appreciate it. I have been playing this save for 10 days now, and don't want to lose it.

The log:
System.NullReferenceException: Object reference not set to an instance of an object
  at RimWorld.StockGeneratorUtility+<TryMakeForStock>c__Iterator175.MoveNext () [0x00000] in <filename unknown>:0
  at RimWorld.StockGenerator_SingleDef+<GenerateThings>c__Iterator17A.MoveNext () [0x00000] in <filename unknown>:0
  at RimWorld.ItemCollectionGenerator_TraderStock.Generate (ItemCollectionGeneratorParams parms, System.Collections.Generic.List`1 outThings) [0x00000] in <filename unknown>:0
  at RimWorld.ItemCollectionGenerator.Generate (ItemCollectionGeneratorParams parms) [0x00000] in <filename unknown>:0
  at RimWorld.PawnGroupKindWorker_Trader.GeneratePawns (RimWorld.PawnGroupMakerParms parms, RimWorld.PawnGroupMaker groupMaker, System.Collections.Generic.List`1 outPawns, Boolean errorOnZeroResults) [0x00000] in <filename unknown>:0
  at RimWorld.PawnGroupKindWorker.GeneratePawns (RimWorld.PawnGroupMakerParms parms, RimWorld.PawnGroupMaker groupMaker, Boolean errorOnZeroResults) [0x00000] in <filename unknown>:0
  at RimWorld.PawnGroupMaker.GeneratePawns (RimWorld.PawnGroupMakerParms parms, Boolean errorOnZeroResults) [0x00000] in <filename unknown>:0
  at RimWorld.PawnGroupMakerUtility+<GeneratePawns>c__IteratorC9.MoveNext () [0x00000] in <filename unknown>:0
  at System.Collections.Generic.List`1[Verse.Pawn].AddEnumerable (IEnumerable`1 enumerable) [0x00000] in <filename unknown>:0
  at System.Collections.Generic.List`1[Verse.Pawn]..ctor (IEnumerable`1 collection) [0x00000] in <filename unknown>:0
  at System.Linq.Enumerable.ToList[Pawn] (IEnumerable`1 source) [0x00000] in <filename unknown>:0
  at RimWorld.IncidentWorker_NeutralGroup.SpawnPawns (RimWorld.IncidentParms parms) [0x00000] in <filename unknown>:0
  at RimWorld.IncidentWorker_TraderCaravanArrival.TryExecute (RimWorld.IncidentParms parms) [0x00000] in <filename unknown>:0
  at RimWorld.Storyteller.TryFire (RimWorld.FiringIncident fi) [0x00000] in <filename unknown>:0
  at RimWorld.IncidentQueue.IncidentQueueTick () [0x00000] in <filename unknown>:0
  at RimWorld.Storyteller.StorytellerTick () [0x00000] in <filename unknown>:0
  at Verse.TickManager.DoSingleTick () [0x00000] in <filename unknown>:0
Verse.Log:Error(String)
Verse.TickManager:DoSingleTick()
Verse.TickManager:TickManagerUpdate()
Verse.Game:UpdatePlay()
Verse.Root_Play:Update()

My mod list is in picture form because I'm too lazy to type out the names of 102 mods. If you can't see them or access them, I'll upload them somewhere else and link to it if that is aloud.

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