Error creating ZIP file bigger then 1Mb

Hello,
i'm facing since many hours with these problem:
When i create a ZIP file that will be bigger than 1024Kb the browser say the following error:
"ERROR: The archive is damaged or its format is unknown."

The code is:

<?php
ini_set("memory_limit", "2000M");

error_reporting(E_ALL);

// Example. Zip all .html files in the current directory and send the file for Download.
$fileDir = './';

include_once("Zip.php");
$fileTime = date("D, d M Y H:i:s T");

$zip = new Zip();
$zip->setComment("Example Zip file.\nCreated on " . date('l jS \of F Y h:i:s A'));
$zip->addFile("Hello World!", "hello.txt");

if ($handle = opendir($fileDir)) {
/* This is the correct way to loop over the directory. */
while (false !== ($file = readdir($handle))) {
if (strpos($file, ".jpg") !== false) {
$pathData = pathinfo($fileDir . $file);
$fileName = $pathData['filename'];

$zip->addFile(file_get_contents($fileDir . $file), $file, filectime($fileDir . $file));
}
}
}

if (ini_get('zlib.output_compression')) {
ini_set('zlib.output_compression', 'Off');
}

$zip->finalize(); // Not scrictly necessary, the next line will call it anyway.
$zipData = $zip->getZipData();
$length = strlen($zipData);

header('Pragma: public');
header("Last-Modified: " . $fileTime);
header("Expires: 0");
header("Accept-Ranges: bytes");
header("Connection: close");
header("Content-Type: application/zip");
header('Content-Disposition: attachment; filename="ZipExample.zip";' );
header("Content-Transfer-Encoding: binary");
header("Content-Length: ". $length);
echo $zipData;
?>

The php.ini sets are:
ZLib Support enabled
Stream Wrapper support compress.zlib://
Stream Filter support zlib.inflate, zlib.deflate
Compiled Version 1.2.3
Linked Version 1.2.3

Directive Local Value Master Value
zlib.output_compression Off Off
zlib.output_compression_level -1 -1
zlib.output_handler no value no value

Thank's
Matteo

Can I get you to send me the problematic Zip (or a sample of the output from a 'safe' directory) at avg [at] grandt.com ?

Or jave a look at the file in either a hex editor or wordpad, it must start with PK and end with null characters (0x00).

Also, I really ought to update the examples, the preferred method for delivering the Zip is

$zip->setZipFile("ZipExample2.zip");

As this will avoid loading the entire Zip binary into memory.

Finalize is called automatically if the zip isn't already finalized.

Alternatively, if you really need to create archices that large, and they consists of multiple files (such as a large directory structure), I'd like to refer to my ZipStream class:
phpclasses.org/package/6616

CORRECTION:

The preferred method of delivering a zip is

$zip->sendZip("ZipExample.zip");