I can't find where the problem is ... if anyone solves please tell me how your narrowed in on it in Firebug or Chrome Developer Tools too would be really helpful too (but not necessary I just want to fix it)
You have a mismatched closing h3 tag here.
<h3> <b>UPCOMING SHOWS</b><br /><h3>
It should be:
<h3> <b>UPCOMING SHOWS</b><br />[B]</h3>[/B]
That b element and the break look redundant to me as you could style the h3 instead to get the gap you want.
You may want to sort out the other errors also as any one could trip a browser up.
The first thing you should do when a page is broken is to validate and catch silly typos and missing tags etc.:)