Open codebase.php of the plugin with a text editor.
Find this:
case 'register.php':
$valid_groups = explode(',', $CAPTCHA_DISABLE['register']);
if (!in_array(USER_GROUP, $valid_groups) OR $CAPTCHA_DISABLE['register'] == '') {
$exper = '(<td colspan="2" align="center" class="tablef">.*
.*<input type="submit" name="submit" value="' . $lang_register_php['submit'] . '" class="button" />.*
.*</td>)';
if (preg_match($exper, $html)) {
$newcpch = '<!-- CAPTCH PLUGIN 3 --><tr><td class="tableb" height="25" width="40%">' . $lang_plugin_captcha_conf . '</td><td class="tableb_compact" colspan="2"><input type="text" name="confirmCode" id="confirmCode" size="5" class="textinput"><img src="captcha.php" align="middle"></tr><tr><td colspan="2" align="center" class="tablef">
<input type="submit" name="submit" value="' . $lang_register_php['submit'] . '" class="button" />
</td></tr>';
$html = preg_replace($exper, $newcpch, $html);
}
}
break;
and replace with
case 'register.php':
$valid_groups = explode(',', $CAPTCHA_DISABLE['register']);
if (!in_array(USER_GROUP, $valid_groups) OR $CAPTCHA_DISABLE['register'] == '') {
$exper = '(<input type="text" style="width: 100%" name="email" maxlength="255" value="" class="textinput" />)';
if (preg_match($exper, $html)) {
$newcpch = '<input type="text" style="width: 100%" name="email" maxlength="255" value="" class="textinput" /></td></tr><!-- CAPTCH PLUGIN 3 --><tr><td class="tableb" height="25" width="40%">' . $lang_plugin_captcha_conf . '</td><td class="tableb_compact" colspan="2"><input type="text" name="confirmCode" id="confirmCode" size="5" class="textinput"><img src="captcha.php" align="middle">';
$html = preg_replace($exper, $newcpch, $html);
}
}
break;