Si, magari hai modificato male la struttura della tabella, controlla il codice html generato.
ecco io ho cambiato solo questo
<tr>
<td colspan="5">
<td colspan="1"> <table>
<tr>
<?php if ($this->params->get('filter')) : ?>
<td align="left" width="60%" nowrap="nowrap">
<?php echo JText::_($this->params->get('filter_type') . ' Filter').' '; ?>
<input type="text" name="filter" value="<?php echo $this->escape($this->lists['filter']);?>" class="inputbox" onchange="document.adminForm.submit();" />
</td>
<?php endif; ?>
<?php if ($this->params->get('show_pagination_limit')) : ?>
<td align="right" width="40%" nowrap="nowrap">
<?php
echo ' '.JText::_('Display Num').' ';
echo $this->pagination->getLimitBox();
?>
</td>
<?php endif; ?>
</tr>
</table>
</td>
</tr>