Multiple windows/instances question

var iu = new ImageUploaderWriter("ImageUploader1", 650, 400); //This was original code, I have tried giving each new instance a unique ID. This solution would look like this:
//var uploadControlId = "ImageUploader" + GenerateRandomNumber();
//var iu = new ImageUploaderWriter(uploadControlId, 650, 400);

iu.activeXControlCodeBase = "../ImageUploader4.cab";
iu.activeXControlVersion = "4,1,1,0";iu.javaAppletCodeBase = "../";
iu.javaAppletCached = true;
iu.javaAppletVersion = "2.1.32.0";
iu.showNonemptyResponse = 'off';
iu.addParam('PaneLayout', 'ThreePanes');
iu.addParam('FolderPaneHeight', '160');
iu.addParam('ShowDebugWindow', 'false');
iu.addParam('AllowMultipleRotate', 'true');
iu.addParam('AllowMultipleRemove', 'true');
iu.addParam('MessageUploadCompleteText', '');
iu.addParam('ButtonSendText', '');
iu.addParam('ShowDescriptions', 'false');
iu.addParam('SplitterLineStyle', 'Solid');
iu.addParam('FileMask', '*.jpg;*.jpe;*.jpeg;*.gif;*.bmp;*.png;*.tif;*.tiff');
iu.addParam('UploadSourceFile', 'false');
iu.addParam('UploadThumbnail1FitMode', 'Fit');
iu.addParam('UploadThumbnail1Height', '120');
iu.addParam('UploadThumbnail1Width', '160');
iu.addParam('UploadThumbnail1JpegQuality', '100');
iu.addParam('UploadThumbnail1ResizeQuality', 'High');
iu.addParam('UncheckUploadedFiles', 'false');
iu.addParam('Action', <URL1, removed for security purposes>);
iu.addEventListener('BeforeUpload', 'ImageUploader_BeforeUpload');
iu.addEventListener('Progress', 'ImageUploader_Progress');
iu.writeHtml();

function ImageUploader_BeforeUpload(){
var imageUploader1 = getImageUploader("ImageUploader1");
imageUploader1.AddField("WorkOrderId", document.getElementById("HiddenFieldWorkOrderId").value);
var imageCount = imageUploader1.getUploadFileCount();

for (var i = 1; i <= imageCount; i++){
imageUploader1.setUploadFileDescription(i,imageUploader1.getUploadFileGuid(i));
}
}

function ImageUploader_Progress(Status, Progress, ValueMax, Value, StatusText) {
var imageUploader1 = getImageUploader("ImageUploader1");
var currentAction = imageUploader1.getAction();
if(Status == 'COMPLETE' && currentAction == URL1, <removed for security purposes>) {
imageUploader1.setAction(URL2, <removed for security purposes>);
imageUploader1.setUncheckUploadedFiles(true);
imageUploader1.setUploadThumbnail1Height(480);
imageUploader1.setUploadThumbnail1Width(640);
imageUploader1.Send();
}
if(Status == 'COMPLETE' && currentAction == URL2, <removed for security purposes>) {
imageUploader1.setAction(URL1, <removed for security purposes>);
imageUploader1.setUncheckUploadedFiles(false);
imageUploader1.setUploadThumbnail1Height(120);
imageUploader1.setUploadThumbnail1Width(160);
CloseUploadPopUp(); 
}
if(Status == 'ERROR') {
alert("An error occurred when uploading your image(s)");
CloseUploadPopUp();
}
}