Troubleshooting file upload error code 4

Try:

foreach ($_FILES["uploadedfile"]["error"] as $key => $error) {
   if ($error == UPLOAD_ERR_OK) {
       echo "$error_codes[$error]";
       move_uploaded_file(
         $_FILES["uploadedfile"]["tmp_name"][$key],
         $target_path
       ) or die("Problems with upload");
   }
}

Well its going to fail as you want to upload MULTIPLE files, but your code is only designed to handle 1 single file.

Go ahead and read through how to handle multiple files here:
http://php.net/manual/en/features.file-upload.multiple.php