Creating default object from empty value

I use drupal 7.2 and i follow this step for installed and show the weather in block position.

1. Download the source module
2. Extract the source and edit weather_data.txt with my personal location.
3. Enabled this module into drupal
4. Go to Configuration -> Weather and Add new display
5. Add location and set as location my personal location
6. Go to Structure and in Block enable weather display

When i updated page i saw this message:
Strict warning: Creating default object from empty value in theme_weather_theming() (line 33 of /var/www/localhost/htdocs/site/sites/all/modules/weather/weather_theme.inc).

And I no clear or fix.
Thanks in advantage for answer and sorry for my bad english