fatal error on settings page

I am running PHP5 on Linux and I am getting the following error if I try to access the settings page:
Fatal error: Only variables can be passed by reference in /home/lohas/drupal47/modules/taxonomy_image/taxonomy_image.module on line 185

The problem is with the first statement in the taxonomy_image_settings function, the category image folder creation.

Instead of:

  if (!file_check_directory(file_create_path(variable_get('taxonomy_image_path', 'category_pictures')), FILE_CREATE_DIRECTORY)) {
    $error = theme('error', t('The picture directory does not exist, or is not writable.'));
  }

it sould read something like:

  $category_pictures_dir = file_create_path(variable_get('taxonomy_image_path', 'category_pictures'));
  if (!file_check_directory($category_pictures_dir, FILE_CREATE_DIRECTORY)) {
    $error = theme('error', t('The picture directory does not exist, or is not writable.'));
  }