eseguire un file bat

[PaTeR]

$descriptorspec = array(
   0 => array("pipe", "r"),  // stdin is a pipe that the child will read from
   1 => array("pipe", "w"),  // stdout is a pipe that the child will write to
   2 => array("file", "error-output.txt", "a") // stderr is a file to write to
);
$res=proc_open("./file.bat", $descriptorspec, $pipes);
echo $res;
proc_close($res); 

sei comunque sicuro che il file file.bat sia nela directory principale?