Maybe try setting some sizes on your tables or something. Its hard to say when I can't fiddle myself. 
I went the other way and got rid of the tables, but still a blank block.
echo '<div style="padding: 5px;" class="smalltext">';
global $context, $settings, $options, $scripturl, $txt, $modSettings;
if( $modSettings['karmaMode'] == 1 )
{
echo '<span class="windowbg2" width="80%" align="left">';
foreach($context['htkarma'] as $htkarma)
{
$total = $htkarma['Good'] - $htkarma['Bad'];'</span>';
echo '<span class="windowbg2" width="20%" align="right">'.$total.'</span>';
}
}
echo '</div>';