The error is:-
window.addEvent is not a function
www.topherstel.nl/xxxxxxxxx
Line 35
This line:-
35 window.addEvent('domready', function(){ var JTooltips = new Tips($$('.hasTip'), { maxTitleChars: 50, fixed: false}); });
36Calendar._DN = new Array ("zondag", "maandag", "dinsdag", "woensdag", "donderdag", "vrijdag", "zaterdag", "zondag");Calendar._SDN = new Array ("zo", "ma", "di", "wo", "do", "vr", "za", "zo"); Calendar._FD = 0; Calendar._MN = new Array ("januari", "februari", "maart", "april", "mei", "juni", "juli", "augustus", "september", "oktober", "november", "december"); Calendar._SMN = new Array ("jan", "feb", "mrt", "apr", "mei", "juni", "juli", "aug", "sept", "okt", "nov", "dec");Calendar._TT = {};Calendar._TT["INFO"] = "Over de kalender";
Looking at your template and the ja_purity one, I can see you are missing this line. (edited to get it to stay in the message):-
script type="text/javascript" src="/media/system/js/mootools.js" script
This is probably something to with the problem; window.addEvent is probably a mootools function.