Just a cosmetic thing, but there aren't enough spaces after the Active Topics link; it's missing one:
<a href="/forums/ubbthreads.php/ubb/calendar">Calendar</a>
<a href="/forums/ubbthreads.php/activetopics/7/1">Active Topics</a>
As you can see, there is a space followed by three others in all of the other links; active topics simply has the three and is neglecting the one... And sadly, i noticed it while working on a theme.