By utilizing a new feature of the upload method this process can be simplified to:

    $ok = $q->upload( $q->param('upload_file1'), '/path/to/write/file.name' );
    if ($ok) {
        print "Uploaded and wrote file OK!";
    } else {
        print $q->cgi_error();
    }

As you can see upload will accept an optional second argument and will write the file to this file path. It will return 1 for success and undef if it fails. If it fails you can get the error from cgi_error.