Go to join_index.html and find this part
{if $diaplayAccountType==true}
<tr>
<td class="ow_label">
{label name='accountType'}
</td>
<td class="ow_value ow_center">
{input name='accountType'}
<br class="ow_no_height" />
{error name='accountType'}
</td>
<td class="ow_desc">
{question_description_lang name="accountType"}
</td>
</tr>
<tr><td colspan="3"> </td></tr>
{/if}
Replace it with this
<!--
{if $diaplayAccountType==true}
<tr>
<td class="ow_label">
{label name='accountType'}
</td>
<td class="ow_value ow_center">
{input name='accountType'}
<br class="ow_no_height" />
{error name='accountType'}
</td>
<td class="ow_desc">
{question_description_lang name="accountType"}
</td>
</tr>
<tr><td colspan="3"> </td></tr>
{/if}
-->
Tell me if this worked or not...