Internet Explorer throws errors when you leave Firebug console messages inside javascript code. To get past them, add following script to your head section of the page:

<script>

if (!window.console || !console.firebug){

    var names = ["log", "debug", "info", "warn", "error", "assert", "dir", "dirxml",

    "group", "groupEnd", "time", "timeEnd", "count", "trace", "profile", "profileEnd"];

    window.console = {};

    for (var i = 0; i < names.length; ++i)

        window.console[names[i]] = function() {}

}

</script>