--- a/src/town_cmd.cpp	Thu Dec 18 18:47:39 2008 +0000
+++ b/src/town_cmd.cpp	Fri Dec 19 01:32:07 2008 +0200
@@ -1310,7 +1310,12 @@
 			_current_company = old_company;
 			return r != 0;
 		}
-		tile = TILE_ADD(tile, ToTileIndexDiff(*ptr));
+        
+        /* Next (valid) tile... */
+        TileIndexDiff dt = ToTileIndexDiff(*ptr);
+
+        if (IsValidTile(tile + dt))
+            tile = TILE_ADD(tile, ToTileIndexDiff(*ptr));
 	}
 
 	/* No road available, try to build a random road block by
@@ -1541,7 +1546,7 @@
 	if (p2 > TSM_CITY) return CMD_ERROR;
 
 	/* Check if too close to the edge of map */
-	if (DistanceFromEdge(tile) < 12)
+	if (DistanceFromEdge(tile) < 1)
 		return_cmd_error(STR_0237_TOO_CLOSE_TO_EDGE_OF_MAP);
 
 	/* Can only build on clear flat areas, possibly with trees. */
@@ -1579,7 +1584,7 @@
 	do {
 		/* Generate a tile index not too close from the edge */
 		TileIndex tile = RandomTile();
-		if (DistanceFromEdge(tile) < 20) continue;
+		if (DistanceFromEdge(tile) < 1) continue;
 
 		/* Make sure the tile is plain */
 		if (!IsTileType(tile, MP_CLEAR) || GetTileSlope(tile, NULL) != SLOPE_FLAT) continue;
@@ -1608,7 +1613,7 @@
 bool GenerateTowns()
 {
 	uint num = 0;
-	uint n = ScaleByMapSize(_num_initial_towns[_settings_game.difficulty.number_towns] + (Random() & 7));
+	uint n = ScaleByMapSize(_num_initial_towns[_settings_game.difficulty.number_towns]) + (Random() & 7);
 	uint num_cities = _settings_game.economy.larger_towns == 0 ? 0 : n / _settings_game.economy.larger_towns;
 
 	SetGeneratingWorldProgress(GWP_TOWN, n);
@@ -1619,7 +1624,7 @@
 		TownSizeMode mode = num_cities > 0 ? TSM_CITY : TSM_RANDOM;
 		if (CreateRandomTown(20, mode, _settings_game.economy.initial_city_size) != NULL) num++;
 		if (num_cities > 0) num_cities--;
-	} while (--n);
+	} while (n && --n);
 
 	/* give it a last try, but now more aggressive */
 	if (num == 0 && CreateRandomTown(10000, TSM_RANDOM, 0) == NULL) {
@@ -1870,7 +1875,12 @@
 			return true;
 		}
 		if (d == DIAGDIR_END) break;
-		tile2 += TileOffsByDiagDir(ReverseDiagDir(d)); // go clockwise
+        
+        // go clockwise
+        TileIndexDiff dt = TileOffsByDiagDir(ReverseDiagDir(d));
+        
+        if (IsValidTile(tile2 + dt))
+    		tile2 += dt; 
 	}
 
 	return false;