Javascript error in VS 2008 web site

I copied an old VS 2008 web site from one PC to another.  This web site runs fine on the old PC.  But I get this error when I run it on my new PC:

JavaScript runtime error: Object doesn't support property or method 'click'

Here is the javascript method that generates the error:

function OnCompleteValidateLogin(Result)

{    

      if (Result != '')

          {        

                alert(Result);    

          }

          else

          {        

                var tdLoginButtonColumn = document.getElementById('tdLoginButtonColumn');        

                var cmdASPLoginButton = tdLoginButtonColumn.childNodes[0];        

                cmdASPLoginButton.click();    

          }

}

It bombs on cmdASPLoginButton.click();

I'm not reat strong with javascript.  I also did not write this method.  I'm confused why it works on the old PC and not the new PC.  Can anyone help me out?

Thanks in advance!