I found a small problem with the pollfield module.

if I create a new forum topic I get always a new poll even if I didn't make it. It is caused by 2 '' characters.

I make a small change in the pollfield.module at row 912.
Original:

  // Question field
  $field = $columns[0];
  $element[$field] = array(
    '#type' => 'textfield',
    '#title' => t('Question'),
    '#rows' => 2,
    '#default_value' => isset($default_value['question']) ? $default_value['question'] : '',
    '#description' => t('The question this poll will ask.'),
  );

Modified:

  // Question field
  $field = $columns[0];
  $element[$field] = array(
    '#type' => 'textfield',
    '#title' => t('Question'),
    '#rows' => 2,
    '#default_value' => isset($default_value['question']) ? $default_value['question'] : "",
    '#description' => t('The question this poll will ask.'),
  );

as you can see I just change '' to ""
This solves my problem