My code looks like this:

<!-- Load Queue widget CSS and jQuery -->
<style type="text/css">
@import url(/css/plupload.queue.css);
</style>
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript">
    google.load("jquery", "1.3");
</script>

<!-- Thirdparty intialization scripts, needed for the Google Gears and BrowserPlus runtimes -->
<script type="text/javascript" src="/plupload/js/gears_init.js"></script>
<script type="text/javascript" src="http://bp.yahooapis.com/2.4.21/browserplus-min.js"></script>

<!-- Load plupload and all it's runtimes and finally the jQuery queue widget -->
<script type="text/javascript" src="/plupload/js/plupload.full.min.js"></script>
<script type="text/javascript" src="/plupload/js/jquery.plupload.queue.min.js"></script>

<script type="text/javascript">
// Convert divs to queue widgets when the DOM is ready
$(function() {
    $("#uploader").pluploadQueue({
        // General settings
        runtimes : 'html5,gears,flash,silverlight,browserplus',    // The first one of these that is available is the one that is used. HTML5 allows drag/drop
        url : 'http://www.vavavid.com/xxfileupload.php',    // The php file that processes the file uploads
        max_file_size : '100mb',
        chunk_size : '1mb',
        unique_names : true,

        // Resize images on clientside if we can
        resize : {width : 320, height : 240, quality : 90},

        // Specify what files to browse for
        filters : [
            {title : "Image files", extensions : "jpg,gif,png,mov,mp4,3gp,avi"},
            {title : "Zip files", extensions : "zip"}
        ],

        // Flash settings
        flash_swf_url : '/plupload/js/plupload.flash.swf',

        // Silverlight settings
        silverlight_xap_url : '/plupload/js/plupload.silverlight.xap'
    });

    // Client side form validation
    $('form').submit(function(e) {
        var uploader = $('#uploader').pluploadQueue();

        // Validate number of uploaded files
        if (uploader.total.uploaded == 0) {
            // Files in queue upload them first
            if (uploader.files.length > 0) {
                // When all files are uploaded submit form
                uploader.bind('UploadProgress', function() {
                    if (uploader.total.uploaded == uploader.files.length)
                        $('form').submit();
                });

                uploader.start();
            } else
                alert('You must at least upload one file.');

            e.preventDefault();
        }
    });
});
</script>
<form ..>
    <div id="uploader">
        <p>You browser doesn't have Flash, Silverlight, Gears, BrowserPlus or HTML5 support.</p>
    </div>
</form>
           

I am using "url : 'http://www.vavavid.com/xxfileupload.php'" to specify the php file to handle the uploaded files. It seems that whatever I give for the url the Plupload code works exactly the same, appearing to upload the files.

I am sure I must be making a rookie error!

That explains the behaviour I have been getting. Thanks. It does seem odd though that Plupload will look to the user as if the files are being uploaded even though they are not!

Yes. Check this one here for example. It demonstrates how to bind an Error event handler among others.

What is the maximum or standard size considered that can be easily uploaded?