Error on changing levels

[fiddlerwoaroof]

Traceback (most recent call last):
  File "main.py", line 390, in <module>
    game_instance.main()
  File "/Users/edwlan/Programming/yinjar_base/yinjar/main.py", line 186, in main
    for x in GameBase.main(self):
  File "/Users/edwlan/Programming/yinjar_base/yinjar/game.py", line 70, in main
    self.handle_keys()
  File "/Users/edwlan/Programming/yinjar_base/yinjar/game.py", line 91, in handle_keys
    _, result = self.mvkeyhandler(self.key, self)
  File "/Users/edwlan/Programming/yinjar_base/yinjar/utilities.py", line 92, in __call__
    result = self.char_handlers[key.c](*a, **kw) or True
  File "/Users/edwlan/Programming/yinjar_base/yinjar/main.py", line 283, in mvkeyhandler
    self.change_level(down=True)
  File "/Users/edwlan/Programming/yinjar_base/yinjar/main.py", line 176, in change_level
    self.setup_map()
  File "/Users/edwlan/Programming/yinjar_base/yinjar/main.py", line 124, in setup_map
    self.MAX_ROOM_MONSTERS, self.MAX_ROOM_ITEMS
  File "/Users/edwlan/Programming/yinjar_base/yinjar/levels.py", line 36, in setup
    self.item_types, max_num_items,
  File "/Users/edwlan/Programming/yinjar_base/yinjar/maps.py", line 296, in populate_map
    while self.is_blocked(x,y):
  File "/Users/edwlan/Programming/yinjar_base/yinjar/maps.py", line 369, in is_blocked
    if self[x][y].blocked:
IndexError: list index out of range