Hello,

I think that line 91 in "open_flash_chart_api.module" :

  $swf = url(variable_get('open_flash_chart_api_library_path', 'sites/all/libraries/ofcv2') . '/open-flash-chart.swf

should be replaced by :

 global $base_url;
  $swf = url($base_url .'/' .variable_get('open_flash_chart_api_library_path', 'sites/all/libraries/ofcv2') . '/open-flash-chart.swf');

because otherwise it is considered as an internal path of drupal.
I had to do that to make the default example in documentation work. I'm running drupal without clean url.