CodingForums.com - Need help with script with window.open, script works in seamonkey but not in IE 8

I have a script that works in seamonkey(my html editor) but when I use it in IE8 it says errors happen.
Here's the code (the first line is on line 7 of the html file):

Code:

<script type="text/javascript">

function enlarge(imageNum)

{

var numToString = "";

if(parseInt(imageNum) < 10){

numToString = "0" + imageNum;

}

else

{

numToString = imageNum + "";

}

window.open("images/LgScreenshot"+numToString+".jpg","Screenshot "+imageNum,"status=0,height=675,width=900,resizable=0");

}

</script>

And the errors:
Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; GTB0.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.5.30729; InfoPath.3; .NET CLR 3.0.30729)
Timestamp: Wed, 10 Feb 2010 14:58:16 UTC

Message: Object expected
Line: 150
Char: 1
Code: 0
URI: http://samssc2site.co.cc/Features.html

Message: Invalid argument.
Line: 18
Char: 1
Code: 0
URI: http://samssc2site.co.cc/Features.html