Why is this keep on happening try to make a fnf mod but this is stoping me


why does it say
source/TitleState.hx:61: characters 16-28 : Type not found : APIStuff
C:/HaxeToolkit/haxe/lib/polymod/git/polymod/format/XMLMerge.hx:189: characters 10-23 : Warning : This typedef is deprecated in favor of haxe.xml.Access
C:/HaxeToolkit/haxe/lib/polymod/git/polymod/format/XMLMerge.hx:189: characters 30-43 : Warning : This typedef is deprecated in favor of haxe.xml.Access
PS C:\Users\Miles\OneDrive\Desktop\Matt mod\Funkin-master>