--- a/src/ai/api/ai_object.cpp	Mon Mar 31 09:51:47 2008 +0000
+++ b/src/ai/api/ai_object.cpp	Mon Mar 31 10:55:13 2008 +0000
@@ -3,6 +3,7 @@
 /** @file ai_object.cpp Implementation of AIObject. */
 
 #include "ai_object.hpp"
+#include "table/strings.h"
 #include "../../command_func.h"
 #include "../../network/network.h"
 #include "../../player_func.h"
@@ -53,6 +54,16 @@
 	return AIObject::GetDoCommandStruct(_current_player)->costs.GetCost();
 }
 
+void AIObject::SetLastError(const StringID last_error)
+{
+	AIObject::GetDoCommandStruct(_current_player)->last_error = last_error;
+}
+
+const StringID AIObject::GetLastError()
+{
+	return AIObject::GetDoCommandStruct(_current_player)->last_error;
+}
+
 void AIObject::SetLastCommandRes(bool res)
 {
 	AIObject::GetDoCommandStruct(_current_player)->last_command_res = res;
@@ -120,6 +131,9 @@
 	CommandCost res;
 	const char *tmp_cmdtext;
 
+	/* Make sure the last error is reset, so we don't give faulty warnings */
+	SetLastError(STR_NULL);
+
 	if (procc != CMD_LANDSCAPE_CLEAR) flags |= DC_AUTO;
 	if (water_protection) flags |= DC_NO_WATER;
 
@@ -129,7 +143,10 @@
 	/* First, do a test-run to see if we can do this */
 	res = ::DoCommand(tile, p1, p2, flags, procc);
 	/* The command failed, so return */
-	if (::CmdFailed(res)) return false;
+	if (::CmdFailed(res)) {
+		SetLastError(_error_message);
+		return false;
+	}
 
 	/* Restore _cmd_text */
 	_cmd_text = tmp_cmdtext;
@@ -172,7 +189,10 @@
 		AI_SuspendPlayer(_current_player, AIObject::GetDoCommandDelay());
 	}
 
-	if (::CmdFailed(res)) return false;
+	if (::CmdFailed(res)) {
+		SetLastError(_error_message);
+		return false;
+	}
 
 	AIObject::IncreaseDoCommandCosts(res.GetCost());
 	return true;