Drupal Form to Select a file.

function crhubTestForm() {
  return drupal_get_form('crhub_crhubTestForm');
}

function crhub_crhubTestForm($form_state) {

  $form['upload_file'] = array(
    '#type' => 'file',
    '#title' => t('File to read')
  );

    //SUBMIT BUTTON
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' =>'Submit',
  );
  return $form;
}
function crhub_crhubTestForm_validate($form, &$form_state) {
  $filePath = $form_state['values']['upload_file'];
  dsm($form_state['values']);
  if ($filePath) {
       if (is_file($filePath)){
         form_set_error('upload_file', "Please enter a file name ");
       }
  }
  else {
    form_set_error('upload_file', "Please enter a file name:");
  }
  /*else {
    if (!is_file($filePath))
      form_set_error('upload_file', 'Please enter a valid file name.');
   *
   */
}
function crhub_crhubTestForm_submit($form, &$form_state) {
  drupal_set_message(t('The form has been submitted.'));
  dsm($form_state['values']);
  /*debug ($form, 'Form ', false); */
  $filePath = $form_state['values']['upload_file'];
  include_once ('CMatArticleHandler.inc');
  $Handler = new CMatArticleHandler($filePath, 'r');
  $Handler->runMain('1');
}