Undefined index: value in nodewords_basic.module

On all of my admin pages I get the following PHP notice:

notice: Undefined index: value in /home/dave/Projects/www/drupal6dev/sites/all/modules/nodewords/nodewords_basic/nodewords_basic.module on line 187.

An empty $content array is being passed to nodewords_basic_canonical_prepare(), which causes problems:

function nodewords_basic_canonical_prepare(&$tags, $content, $options) {
  $content['value'] = trim($content['value'], '/');

  if (empty($content['value'])) {
    $path = '';
    ...