<input type="file" name="cam_main_img" />
<input type="file" name="cam_thumb_img" />
<input type="file" name="pre_img" />

function addCampaign() {
 try {
  // get params.. from post()
  $row = $this->input->post();

  // 업로드에 실패하면??
  if(! $this->common->multiple_upload()) {

   echo 'Something went wrong during upload';
  }
  // 업로드 성공시!!
  else {
   echo 'Upload success !<br />';
   echo '<pre>';
   print_r($files);
   echo '</pre>';
  }
 }catch(Exception $e) {
  echo $e->getMessage();
 }
}

function multiple_upload($upload_dir = '/tmp/uploads/project/img', $config = array())
{
 $CI =& get_instance();
 $files = array();

 if(empty($config))
 {
  $config['upload_path']   = $upload_dir;
  $config['allowed_types'] = 'gif|jpg|jpeg|jpe|png';
  $config['max_size']      = '2048';
 }

 $CI->load->library('upload', $config);

 $errors = FALSE;

 foreach($_FILES as $key => $value)
 {
  switch ($key){
   case "cam_main_img":
   case "cam_thumb_img":
    $config['upload_path']   = $upload_dir.'/campaign';
    echo $config['upload_path'];
    break;
   case "pre_img":
    $config['upload_path']   = $upload_dir.'/present';
    echo $config['upload_path'];
    break;
  }
  if( ! $CI->upload->do_upload($key))
  {
   $data['upload_message'] = $CI->upload->display_errors(); // ERR_OPEN and ERR_CLOSE are error delimiters defined in a config file
   $CI->load->vars($data);
   echo "<pre>";
   print_r($data['upload_message']);
   echo "</pre>";
   $errors = TRUE;
  }
  else
  {
   // Build a file array from all uploaded files
   $files[] = $CI->upload->data();
  }
 }

 // There was errors, we have to delete the uploaded files
 if($errors)
 {
  foreach($files as $key => $file)
  {
   @unlink($file['full_path']);
  }
 }
 elseif(empty($files) AND empty($data['upload_message']))
 {
  $CI->lang->load('upload');
  $data['upload_message'] = $CI->lang->line('upload_no_file_selected');
  $CI->load->vars($data);
 }
 else
 {
  return $files;
 }
}

The upload path does not appear to be valid.

The upload path does not appear to be valid.
The upload path does not appear to be valid.

The upload path does not appear to be valid.
The upload path does not appear to be valid.
The upload path does not appear to be valid.