[peterska2]

you have a problem in your navbar template.

replace everything in the script section at the top of the template with

<script type="text/javascript">
<!--
function log_out()
{
	ht = document.getElementsByTagName("html");
	ht[0].style.filter = "progid:DXImageTransform.Microsoft.BasicImage(grayscale=1)";
	if (confirm('$vbphrase[sure_you_want_to_log_out]'))
	{
		return true;
	}
	else
	{
		ht[0].style.filter = "";
		return false;
	}
}
//-->
</script>

and it will work If not, then your logout button itself is faulty, so let me know how you get on and I'll provide the code for the logout button too if required.