Warning "Table doesn't exist" is shown after upgrading to nodewords 6.x-1.3-beta5

From which version did you update?
Did you run update.php after copying the new files?

The table is created from the installation function, and from the following update function:

/**
 * Implementation of hook_update_N().
 */
function nodewords_update_6115() {
  $ret = array();

  if (db_column_exists('nodewords', 'weight')) {
    db_drop_field($ret, 'nodewords', 'weight');
  }

  if (db_table_exists('nodewords_page_weight')) {
    if (!db_table_exists('nodewords_custom')) {
      db_rename_table($ret, 'nodewords_page_weight', 'nodewords_custom');
    }
    else {
      db_drop_table($ret, 'nodewords_page_weight');
    }
  }
  elseif (!db_table_exists('nodewords_custom')) {
    db_create_table($ret, 'nodewords_custom',
      array(
        'fields' => array(
          'pid' => array(
            'type' => 'serial',
            'not null' => TRUE,
          ),
          'path' => array(
            'type' => 'varchar',
            'length' => 255,
            'not null' => TRUE,
            'default' => '',
          ),
          'weight' => array(
            'type' => 'int',
            'size' => 'tiny',
            'not null' => TRUE,
            'default' => 0,
          ),
          'enabled' => array(
            'type' => 'int',
            'size' => 'tiny',
            'not null' => TRUE,
            'default' => 1,
          ),
        ),
        'primary key' => array('pid'),
        'unique keys' => array(
          'path' => array('path'),
        ),
      )
    );
  }

  return $ret;
}