--- a/src/terraform_gui.cpp	Tue Jan 29 14:17:13 2008 +0000
+++ b/src/terraform_gui.cpp	Tue Jan 29 14:19:07 2008 +0000
@@ -385,7 +385,7 @@
 
 static void PlaceProc_LightHouse(TileIndex tile)
 {
-	if (!IsTileType(tile, MP_CLEAR) || IsSteepSlope(GetTileSlope(tile, NULL)) || IsBridgeAbove(tile)) {
+	if (!IsTileType(tile, MP_CLEAR) || GetTileSlope(tile, NULL) != SLOPE_FLAT || IsBridgeAbove(tile)) {
 		return;
 	}
 
@@ -396,7 +396,7 @@
 
 static void PlaceProc_Transmitter(TileIndex tile)
 {
-	if (!IsTileType(tile, MP_CLEAR) || IsSteepSlope(GetTileSlope(tile, NULL)) || IsBridgeAbove(tile)) {
+	if (!IsTileType(tile, MP_CLEAR) || GetTileSlope(tile, NULL) != SLOPE_FLAT || IsBridgeAbove(tile)) {
 		return;
 	}