Problem with javascript from Flash

Hi all,
I have posted the start of this in the client-side forum but I am realizing it should probably be posted here.

I am using a javascript to open a new centered “pop-up”-window from Flash. It’s simple and I haven’t needed to use it for a long time. Now it doesn’t work in Explorer (8). I have tried two different scripts actually, at least one originally coming from Kirupa’s tutorials.
It works fine in Safari, Firefox and Opera for MAC. It also works in Google Chrome on PC (haven’t had a chance to try in Firefox/PC yet). In Explorer I get an: “Error in page” message in the status-field and when making an error-search in the webdeveloper tool, it displays “non-valid argument” for this line:

win = window.open(page,winName,config);

I also made a php-page with the same script and a text-based link. Then the pop-up window opens like it should…

Here is the code on the button in Flash:

openPopupBUTTON.onRelease = function() {
    getURL ("javascript:newWin('popupwindow.php','popupname','620','361','0','0')"); 
}

and in the php-page holding the swf:

<script language="JavaScript" type="text/JavaScript">
<!--

function newWin(page,winName,w,h,scrollb,resize) {

var win=null;

centerWidth = (screen.width) ? (screen.width-w)/2 : 0;

centerHeight = (screen.height) ? (screen.height-h)/2 : 0;

config = 'height='+h+',width='+w+',top='+centerHeight+',left='+centerWidth+',scrollbars='+scrollb+',resizable='+resize+''

win = window.open(page,winName,config);

}
//-->
</script>

What is wrong?:puzzled: Or, does anyone have a better solution?