--- a/src/ai/api/ai_town.cpp	Sun Mar 18 19:39:27 2007 +0000
+++ b/src/ai/api/ai_town.cpp	Sun Mar 18 19:52:09 2007 +0000
@@ -25,6 +25,7 @@
 
 char *AITown::GetName(TownID town_id)
 {
+	if (!this->IsValidTown(town_id)) return NULL;
 	static const int len = 64;
 	char *town_name = MallocT<char>(len);
 
@@ -36,12 +37,14 @@
 
 int32 AITown::GetPopulation(TownID town_id)
 {
+	if (!this->IsValidTown(town_id)) return 0;
 	const Town *t = ::GetTown(town_id);
 	return t->population;
 }
 
 TileIndex AITown::GetLocation(TownID town_id)
 {
+	if (!this->IsValidTown(town_id)) return INVALID_TILE;
 	const Town *t = ::GetTown(town_id);
 	return t->xy;
 }