no s?? si esto se deba a los headers:
header (”Expires: Mon, 26 Jul 2005 05:00:00 GMT”);
header (”Last-Modified: ” . gmdate(”D,d M YH:i:s”) . ” GMT”);
header (”Cache-Control: no-cache, must-revalidate”);
header (”Pragma: no-cache”);
header (’Content-type: application/xls’);
header (”Content-Disposition: attachment; filename=\”" . $filename . “\”" );

HELP meeee!!!!

selectFont(???../fonts/courier.afm???);
$pdf->ezSetCmMargins(1,1,1.5,1.5);

$conexion = mysql_connect(???localhost???, ???root???, ???a???);
mysql_select_db(???lubricentro???, $conexion);
$queEmp = ???SELECT nombre_producto, marca_producto, descripcion_p, cantidad_stock FROM producto???;
$resEmp = mysql_query($queEmp, $conexion) or die(mysql_error());
$totEmp = mysql_num_rows($resEmp);

mysql_select_db(???salud???, $conexion);

$ixx = 0;
while($datatmp = mysql_fetch_assoc($resEmp))
{
$ixx = $ixx+1;
$data[] = array_merge($datatmp, array(???num???=>$ixx));
}
$titles = array(
???nombre_producto???=>???nombre_producto???,
???marca_producto???=>???marca_producto???,
???descripcion_p???=>???descripcion_p???,
???cantidad_stock???=>???cantidad_stock???
);
$options = array(
???shadeCol???=>array(0.9,0.9,0.9),
???xOrientation???=>???center???,
???width???=>500
);

$txttit = ???BLOG.UNIJIMPE.NET\n???;
$txttit.= ???Ejemplo de PDF con PHP y MYSQL \n???;
$pdf->ezText($txttit, 12);
$pdf->ezTable($data, $titles, ???, $options);
$pdf->ezText(???\n\n\n???, 10);
$pdf->ezText(???Fecha: ???.date(???d/m/Y???), 10);
$pdf->ezText(???Hora: ???.date(???H:i:s???).???\n\n???, 10);
$pdf->ezStream();

?>

me sale esto:

Warning: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\lubricentro\pdfprueba.php:1) in C:\AppServ\www\lubricentro\class.pdf.php on line 1916

Warning: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\lubricentro\pdfprueba.php:1) in C:\AppServ\www\lubricentro\class.pdf.php on line 1917

Warning: Cannot modify header information - headers already sent by (output started at C:\AppServ\www\lubricentro\pdfprueba.php:1) in C:\AppServ\www\lubricentro\class.pdf.php on line 1919
%PDF-1.3 %???????? 1 0 obj endobj 2 0 obj endobj 3 0 obj << /Type /Pages /Kids [6 0 R ] /Count 1 /Resources << /ProcSet 4 0 R /Font >> /MediaBox [0.000 0.000 595.280 841.890] >> endobj 4 0 obj [/PDF /Text ] endobj 5 0 obj endobj 6 0 obj endobj 7 0 obj stream x??}???KS??0?????????????????&M??`??X h]??bjZ?????\??????u??un2??????|???9????? ScN ??Fb????#??#A??
????n??x????^O????Iz ?????????a??@&??)???????}???? /`y5??JXN?????
????????? N????+??????uB????????X?y??4??????v??8(?????;???w????.?????????????]??n????s6S17????}V??,Dr#???G??????g????????? @??O???????????g?????P???????????a7N????X????? F??????Q????????m?????? endstream endobj 8 0 obj endobj 9 0 obj stream x??????????R??0E{?????????lY%????P??????????A??l1??3????q??H?????-hT??9gWw6{??@*RH J???DS U O?? ??
????yo]o?????????*??rB??????7????O$p]. \8????t????q??????????????*J??.cx.????_e0c??i??O????????[s??C?? ??2????BQe??t?? ??&????????????oB??T!????\??d??b????K??9??]NQ?????????? (??C??a7rl?????]??%Y???\????FWrI??????j??K??|J??d~??????????(??$p??????s??????x????????????&E+
4]M endstream endobj xref 0 10 0000000000 65535 f 0000000015 00000 n 0000000080 00000 n 0000000126 00000 n 0000000280 00000 n 0000000309 00000 n 0000000414 00000 n 0000000487 00000 n 0000000895 00000 n 0000001002 00000 n trailer startxref 1396 %%EOF

para 15.000 usuarios creo que tardara pero luego implantare el sistema y te cuento.