Fixed in the last update, thanks

Your mod specifies that Vanilla Expanded Framework is required, but it's not specified in the about.xml.

If this is the case, the following is missing in your About.xml

@Erazil Thanks friend!

[Analyzer] Mod Mythic Ages: Megafauna Bestiary has packaged the base-game Rimworld assemblies
UnityEngine.StackTraceUtility:ExtractStackTrace ()
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.Log.Error_Patch1 (string)
Analyzer.Profiling.ThreadSafeLogger:Error (string) (at C:/Program Files (x86)/Steam/steamapps/common/RimWorld/Mods/Dubs-Performance-Analyzer/Source/Profiling/Utility/ThreadSafeLogger.cs:64)
Analyzer.Profiling.StackTraceUtility:Initialise () (at C:/Program Files (x86)/Steam/steamapps/common/RimWorld/Mods/Dubs-Performance-Analyzer/Source/Profiling/StackTrace.cs:160)
Analyzer.Modbase:.ctor (Verse.ModContentPack) (at C:/Program Files (x86)/Steam/steamapps/common/RimWorld/Mods/Dubs-Performance-Analyzer/Source/Modbase.cs:76)
System.Reflection.RuntimeConstructorInfo:InternalInvoke (object,object[],bool)
System.Reflection.RuntimeConstructorInfo:DoInvoke (object,System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo)
System.Reflection.RuntimeConstructorInfo:Invoke (System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo)
System.RuntimeType:CreateInstanceImpl (System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo,object[],System.Threading.StackCrawlMark&)
System.Activator:CreateInstance (System.Type,System.Reflection.BindingFlags,System.Reflection.Binder,object[],System.Globalization.CultureInfo,object[])
System.Activator:CreateInstance (System.Type,object[])
Verse.LoadedModManager:CreateModClasses ()
Verse.LoadedModManager:LoadAllActiveMods (bool)
Verse.PlayDataLoader:DoPlayLoad ()
Verse.PlayDataLoader:LoadAllPlayData (bool)
Verse.Root/<>c:<Start>b__10_1 ()
Verse.LongEventHandler:RunEventFromAnotherThread (System.Action)
Verse.LongEventHandler/<>c:<UpdateCurrentAsynchronousEvent>b__28_0 ()
System.Threading.ThreadHelper:ThreadStart_Context (object)
System.Threading.ExecutionContext:RunInternal (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool)
System.Threading.ExecutionContext:Run (System.Threading.ExecutionContext,System.Threading.ContextCallback,object,bool)
System.Threading.ExecutionContext:Run (System.Threading.ExecutionContext,System.Threading.ContextCallback,object)
System.Threading.ThreadHelper:ThreadStart ()

here is the same error some other guys had on startup, since you asked for it it seems to be the same.

seems to be only for dubs performance users, you might have let some vanilla code in here from what i understand it checked it don't know if intended or not (im no modder just learnt a bit how to understand my thousands of red errors to know if it's the "it doesn't matter" or the "i might have to do something" kind of error).

also i just discovered this mod and as a fan of dark ages too i find it really interesting for my playthrough but it is already loaded will i need to add some of the mod buildings with dev mode or do they spawn naturally ?

The error occurred because the latest update mistakenly included base game assemblies within the mod's Assemblies folder. RimWorld already loads these files by default, so when the mod tried to load them again, the game detected duplicates and displayed red errors during launch. I released a hotfix that removes unnecessary files from this folder and keeps only the mod's own DLL, restoring normal functionality. The mod version that is fixed is 1.1.1, the most recent.

Thanks for the quick fix

Also, about your doubt about the new building feature, you can see it in two ways: at the start of the RUN when there's a chance of at least one spawning (Nest priority) depending on the biomes.

And through in-game events, it has the same chance of spawning as a Raid. You don't need to download any mods or dependencies to make it work.

Hope you like it.