One of the Ftp servers, I am harvesting from is not using the default 21 port.
Can you add the option to specify the port num when setting up the FTP Configuration.
http://w3schools.com/PHP/func_ftp_connect.asp

I am still new to using drupal forms so I might make mistakes in my draft here,

Added the form item for
For the media_mover_ftp.module
in function media_mover_ftp_config($configuration) {

after the line 183

  $form['mm_ftp_conf']['mm_ftp_portnum'] = array(
    '#title' => t('FTP Port Number'),
    '#type' => 'textfield',
    '#default_value' => $configuration['mm_ftp_portnum'],
    '#description' => t('Enter number for the FTP Port Number. Default is 21.'),    
    '#size' => 5  //not sure this should be larger than 5
  );

For the media_mover_ftp.module
in function media_mover_ftp_connect($configuration, $display = false) {

change the line to 

  $connection['ftp_connection'] = ftp_connect($configuration['mm_ftp_host'], $configuration['mm_ftp_portnum']);

I didn't see the validate form and I am bit iffy on how to get the validation to work for this when there is a fieldset in the form.
['mm_ftp_conf']

/**
 * Validate the configuration form.
 */
function _validate($form, $form_state) {
  $portnum = $form_state['values']['mm_ftp_portnum']
  if (!is_numeric($portnum)){
    form_set_error('mm_ftp_portnum', t('Please enter a number for the Port Number.'));
  }
}