problema con gli apici

[prinzart]

nel codice se metto il nome del pdf me lo apre senza problemi:

<?php
require('../inc_function.php');


$query22="SELECT *
           FROM c_upload_file
           WHERE c_upload_file.id_upload_file=$foto";
$ris_query22=mysql_query($query22, $conn);
$row22=mysql_fetch_array($ris_query22);    

require('fpdi.php');

$pdf =& new FPDI();

$pagecount = $pdf->setSourceFile('/web/htdocs/www.sito.it/home/amministrazione_file/ALL_MRTCR_MODULO_RICH_INT_TECNICO.pdf');
$tplidx = $pdf->importPage(1, '/MediaBox');

$pdf->addPage();
$pdf->useTemplate($tplidx, 10, 10, 90);

$pdf->Output();
?>

come posso invece mettere una variabile al posto del nome? Ho fatto così ma mi da errore
(Parse error: syntax error, unexpected T_STRING in /web/htdocs/www.sito.it/home/print/stampa_file_sharing.php on line 15):

<?php
require('../inc_function.php');


$query22="SELECT *
           FROM c_upload_file
           WHERE c_upload_file.id_upload_file=$foto";
$ris_query22=mysql_query($query22, $conn);
$row22=mysql_fetch_array($ris_query22);    

require('fpdi.php');

$pdf =& new FPDI();

$pagecount = $pdf->setSourceFile('/web/htdocs/www.sito.it/home/amministrazione_file/$row22['file']');
$tplidx = $pdf->importPage(1, '/MediaBox');

$pdf->addPage();
$pdf->useTemplate($tplidx, 10, 10, 90);

$pdf->Output();
?>