--- a/src/ai/api/ai_object.hpp	Thu Apr 03 22:09:54 2008 +0000
+++ b/src/ai/api/ai_object.hpp	Thu Apr 03 22:18:52 2008 +0000
@@ -40,7 +40,7 @@
 		AIObject *mode_instance;
 		uint delay;
 		CommandCost costs;
-		StringID last_error;
+		uint last_error;
 		bool last_command_res;
 		VehicleID new_vehicle_id;
 		SignID new_sign_id;
@@ -76,13 +76,14 @@
 
 	/**
 	 * Set the DoCommand last error.
+	 * @note last_error is an ERR_* from a ErrorMessages enum.
 	 */
-	static void SetLastError(const StringID last_error);
+	static void SetLastError(uint last_error);
 
 	/**
 	 * Get the DoCommand last error.
 	 */
-	static StringID GetLastError();
+	static uint GetLastError();
 
 	/**
 	 * Set the current mode of your AI to this proc.