Hi Ken,

I'm not that I understand. Here is part of my code: 

<CuteWebUI:Uploader runat="server" ID="Uploader1" ManualStartUpload="true" 
                       MultipleFilesUpload="false" InsertButtonID="btnSelectFiles" 
                       ProgressCtrlID="pnlProgress" ProgressTextID="lblProgress"  ProgressPanelWidth="270"
                       CancelButtonID="btnCancelUpload"  OnFileUploaded="Uploader_FileUploaded"
                        ProgressInfoStyle="display:none"   ProgressPicture="images/dropbox/pb.jpg" FileTypeNotSupportMsg="This file type is not allowed"    
                        ProgressBarBackgroundImage="images/dropbox/pb_bg.jpg" ProgressBarHeight="11" ProgressBarBorderStyle="height:0; margin-left:4px;" ProgressBarStyle="Continuous" >

 <ValidateOption MaxSizeKB="2097152" AllowedFileExtensions=".zip,.doc,.docx,.xls,.xlsx,.ppt,.pptx,.pdf,.gif,.tiff,.jpg,.png,.bmp,.wmv,.avi,.mp4,.rtf,.txt" />
                    </CuteWebUI:Uploader>

I would like the message "This file type is not allowed" to not use the default java script alert and instead display it on the page or use a custom lightbox. The events you mentoined are not fired and I still get a js alert with the mentioned message.

What am I doing wrong? 

Thanks