- fixed: IDs that map to nothing must be removed from the spawn/conversation ID maps.

src/p_things.cpp

@@ -659,9 +659,13 @@ void InitClassMap(FClassMap &themap, SpawnMap &thedata)
 					pair->Value.filename.GetChars(), pair->Value.linenum, pair->Value.classname.GetChars());
 				error++;
 			}
-		}
 			themap.Insert(pair->Key, cls);
 		}
+		else
+		{
+			themap.Remove(pair->Key);
+		}
+	}
 	if (error > 0)
 	{
 		I_Error("%d unknown actor classes found", error);