Object Required Error.

I've been ask to do a pasting an copied image from clipboard to Web Form and directly upload in web server. I've found some TUTORIAL about it, But its been dead for almost 4 years, I need someone to guide me, Im new in programming im currently taking my Internship as a programmer of php.

I could paste the image from Clipboard to Web Form, But when i start uploading it onto the server, i got this error "Object Required". I can't seem find a way to fix it.

function uplImages()
            {                                         
              flagUploadingStarted = true;
                    // Uploading Image 1 if its present.
                    if(document.getElementById("<%=hdnImageFileName1.Id%>").value != "")
                    {            
                        uploadImage1(document.getElementById("<%=hdnImageFileName1.Id%>").value) // This where i get the "Object Required"
                    }
            }

Thanks. Anyhelp would be really appreciated.