Stack overflow at line 0, prototype + scriptaculous

Hvorfor virker dette ikke??..

Jeg får fejlen: stack overflow at line 0!

<script type="text/javascript" src="./javascript/prototype/prototype.js"></script>
<script type="text/javascript" src="./javascript/scriptaculous/scriptaculous.js"></script>

<div id="main" style="display:none;">
TEST TEST TEST
</div>

<script>
    new Effect.Appear('main');
</script>