At the moment this image is called like :

  $alt_content = l(theme_image('http://www.adobe.com/images/shared/download_buttons/get_flash_player.gif', 'Get Adobe Flash player', 'Get Adobe Flash player', null, false), 'http://www.adobe.com/go/getflashplayer', array('html' => TRUE));

But this creates problem with IE when you are using https.
Could we change the beginning of the function into something like :

  // Add SWFObject script if required
  if ( variable_get('open_flash_chart_api_use_swfobject', false) ) {
    drupal_add_js(variable_get('open_flash_chart_api_library_path', 'sites/all/libraries/ofcv2') . '/js/swfobject.js');
  }

  // Generate code to provide data when rendering chart using JavaScript method
  if ($data['@method'] == 'get-data') {
    $js = 'function @id() { return @json; }';
    $js = str_replace(array_keys($data), array_values($data), $js);
    drupal_add_js($js, 'inline', 'header');
  }
  if ( isset($_SERVER['HTTPS']) || ($_SERVER['HTTPS'] == 'on') ) {
    $protocol = 'https';
  } else {
    $protocol = 'http';
  }
  // Alternative content to display when Flash player is not installed
  $alt_content = l(theme_image($protocol . '://www.adobe.com/images/shared/download_buttons/get_flash_player.gif', 'Get Adobe Flash player', 'Get Adobe Flash player', null, false), 'http://www.adobe.com/go/getflashplayer', array('html' => TRUE));