Got the installer working. Fixed a few bugs including a nasty-to-debug issue where the lang_id was being hardcoded during installation, resulting in strings being inserted with the wrong lang_id causing an infinfinite loop with fetch() throwing a "no strings" error and using template (which calls fetch()) to complain
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>blank_page</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link href="css/blank.css" rel="stylesheet" type="text/css" />
<base target="_self" />
<script type="text/javascript">
function init() {
if (parent.tinymce.isIE)
document.body.contentEditable = true;
else
document.designMode = 'on';
parent.initIframe(document);
window.focus();
}
</script>
</head>
<body onload="init();">
</body>
</html>