Fixing an old mod, or trying to

[Madura]

Hello I am new to this whole thing, but I am trying to fix an old mod, and it keeps throwing an error this is the error message.

Error in static constructor of ZzZomboRW.HarmonyHelper: System.TypeInitializationException: The type initializer for 'ZzZomboRW.HarmonyHelper' threw an exception. ---> HarmonyLib.HarmonyException: Patching exception in method null ---> System.ArgumentException: Undefined target method for patch method static System.Void ZzZomboRW.PathFinder_FindPathPatch::Prefix(ZzZomboRW.Building_Cage[]& __state, Verse.Map ___map, Verse.IntVec3& start, Verse.LocalTargetInfo& dest, Verse.TraverseParms traverseParms, Verse.AI.PathEndMode peMode)
  at HarmonyLib.PatchClassProcessor.PatchWithAttributes (System.Reflection.MethodBase& lastOriginal) [0x00047] in <255414689d344b1385ae719f6cce8c55>:0
  at HarmonyLib.PatchClassProcessor.Patch () [0x00068] in <255414689d344b1385ae719f6cce8c55>:0
   --- End of inner exception stack trace ---
  at HarmonyLib.PatchClassProcessor.ReportException (System.Exception exception, System.Reflection.MethodBase original) [0x00127] in <255414689d344b1385ae719f6cce8c55>:0
  at HarmonyLib.PatchClassProcessor.Patch () [0x00093] in <255414689d344b1385ae719f6cce8c55>:0
  at HarmonyLib.Harmony.<PatchAll>b__10_0 (System.Type type) [0x00007] in <255414689d344b1385ae719f6cce8c55>:0
  at HarmonyLib.CollectionExtensions.Do[T] (System.Collections.Generic.IEnumerable`1[T] sequence, System.Action`1[T] action) [0x00014] in <255414689d344b1385ae719f6cce8c55>:0
  at HarmonyLib.Harmony.PatchAll (System.Reflection.Assembly assembly) [0x00006] in <255414689d344b1385ae719f6cce8c55>:0
  at HarmonyLib.Harmony.PatchAll () [0x0001b] in <255414689d344b1385ae719f6cce8c55>:0
  at ZzZomboRW.HarmonyHelper..cctor () [0x0000a] in <4b44e491691f4cafa99608f82d19cdef>:0
   --- End of inner exception stack trace ---
  at (wrapper managed-to-native) System.Runtime.CompilerServices.RuntimeHelpers.RunClassConstructor(intptr)
  at System.Runtime.CompilerServices.RuntimeHelpers.RunClassConstructor (System.RuntimeTypeHandle type) [0x0002a] in <eae584ce26bc40229c1b1aa476bfa589>:0
  at (wrapper dynamic-method) Verse.StaticConstructorOnStartupUtility.Verse.StaticConstructorOnStartupUtility.CallAll_Patch1()
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) Verse.Log:Verse.Log.Error_Patch1 (string)
(wrapper dynamic-method) Verse.StaticConstructorOnStartupUtility:Verse.StaticConstructorOnStartupUtility.CallAll_Patch1 ()
Verse.PlayDataLoader/<>c:<DoPlayLoad>b__4_5 ()
Verse.LongEventHandler:ExecuteToExecuteWhenFinished ()
Verse.LongEventHandler:UpdateCurrentAsynchronousEvent ()
Verse.LongEventHandler:LongEventsUpdate (bool&)
(wrapper dynamic-method) Verse.Root:Verse.Root.Update_Patch1 (Verse.Root)
Verse.Root_Entry:Update ()

I don't know how to fix this, but if anyone knows I would be very happy, and thank you greatly