Our main logo is link to www.jboss.org but in browser it's not clickable.

seems that one DIV is the culprit (just before "container" DIV):
<div style="position: absolute; top: 0px; left: 0px; width: 30%; padding: 0px; margin: 0px;"><div style="position: relative; height: 28px;"></div></div>

I have no idea why this DIV is there because when i removed it in Firebug design was OK and logo now became clickable.