There is a duplicated </td> in styles/subsilver2/template/catpcha_qa.html

FIND:
<td class="row2"><input class="post" type="text" name="qa_answer" size="80" /></td>
<input type="hidden" name="qa_confirm_id" id="confirm_id" value="

{QA_CONFIRM_ID}" /></td>

REPLACE WITH:
<td class="row2"><input class="post" type="text" name="qa_answer" size="80" /><input type="hidden" name="qa_confirm_id" id="confirm_id" value="{QA_CONFIRM_ID}

" /></td>