ICON loading error?

Do you know why the map module try to loading loading.jpg from wrong location?

Here is a log

Process Process-1:
Traceback (most recent call last):
File "C:\Python27\lib\multiprocessing\process.py", line 232, in _bootstrap
self.run()
File "C:\Python27\lib\multiprocessing\process.py", line 88, in run
self._target(_self._args, *_self._kwargs)
File "C:\Python27\MAVProxy-master\MAVProxy..\MAVProxy\modules\mavproxy_map\mp_slipmap.py", line 610, in child_task
max_zoom=self.max_zoom)
File "C:\Python27\MAVProxy-master\MAVProxy..\MAVProxy\modules\mavproxy_map\mp_tile.py", line 198, in __init__
self._loading = mp_icon('loading.jpg')
File "C:\Python27\MAVProxy-master\MAVProxy..\MAVProxy\modules\mavproxy_map\mp_tile.py", line 577, in mp_icon
raw = open(os.path.join(__file__, 'data', filename)).read()
IOError: [Errno 2] No such file or directory: 'C:\Python27\MAVProxy-master\MAVProxy\..\MAVProxy\modules\mavproxy_map\mp_tile.pyc\data\loading.jpg'

Start with MAVProxy/modules/mavproxy_map/mp_tile.py at mp_icon and the call from mp_slipmap.py:610. Inspect how the loading.jpg path is built when running from the compiled .pyc location. Done means the map module can locate loading.jpg without the reported IOError.

Written by the indexing model from the issue text.