Problema con window.open

Qualcuno può dirmi perchè questo codice in locale e su altri host funziona e su altervista no ?
[code:1:6eedc5073b]function OpenShot(H, W, image)
{
shotWin = window.open('', 'shot', 'height='+H+', width='+W+', top=0, left=0, resizable=yes, scrollbars=yes');

shotWin.document.open();
shotWin.document.writeln("<!doctype html public '-//W3C//DTD HTML 4.01 Transitional//EN'>");
shotWin.document.writeln("<html>&qu ot;);
shotWin.document.writeln("<head>&qu ot;);
shotWin.document.writeln("<meta http-equiv='Content-Type' content='text/html; charset=ISO-8859-1'>");
shotWin.document.writeln("<title>Al e\'s GP page - Screenshot</title>");
shotWin.document.writeln("<link rel='stylesheet' type='text/css' href='../../gp_page.css'>");
shotWin.document.writeln("</head>");
shotWin.document.writeln("");
shotWin.document.writeln("<body>&qu ot;);
shotWin.document.writeln("<input id='but' class='FormButton' type='button' value='Close' onclick='window.close()'>");
shotWin.document.writeln("<div>&amp ;nbsp;</div>");
shotWin.document.writeln("<img src='" + image + "' alt=''>");
shotWin.document.writeln("</body>");
shotWin.document.writeln("</html>");
shotWin.document.close();
}
[/code:1:6eedc5073b]

e viene richiamato con:
[code:1:6eedc5073b]<a href="#" onclick="OpenShot('480', '440', '../../images/cc4_overview.gif');" onmouseover="window.status=''; return true"><img src="../../images/cc4_overview_small.gif" alt="Click to enlarge" width="200" height="203" border="0"></a>[/code:1:6eedc5073b]

se volete vederlo all'opera:
http://alexcar.altervista.org/gp4/eng/pe4_eng.html

Grazie