hvorfor redirecter den ikke?

Jeg har selv MSIE 5.0, men den directer til start_old.asp - hvorfor redirecter den mig ikke til start_new.asp, som den skal???

<script LANGUAGE="javascript">
<!--
browser_name = navigator.appName;
browser_version = parseFloat(navigator.appVersion);

if (navigator.javaEnabled() < 1)
{self.location = 'start_old.asp';}
else if (browser_name == "Netscape" && browser_version < 4.0)
{self.location = 'start_old.asp';}
else if (browser_name == "Netscape" && browser_version >= 4.0)
{self.location = 'start_old.asp';}
else if (browser_name == "Microsoft Internet Explorer" && browser_version < 4.0)
{document.location = 'start_old.asp';}
else if (browser_name == "Microsoft Internet Explorer" && browser_version >= 5.0)
{document.location = 'start_new.asp';}
else {self.location = 'start_old.asp';}
//-->
</script>