yes, i found it still had problems so i changed the links to use the full url via bloginfo(‘url’).
replace lines 107 – 120 with below:
<table style="width:100%">
<tr>
<td align="left" valign="middle" width="100">
Security Code:<br />
<input type="text" name="publicKey" style="width:90px;" maxlength="6" tabindex="5" class="textfield" />
</td>
<td align="left" valign="bottom" width="100">
<img id="simple_captcha" src="<?php bloginfo('url'); ?>/wp-content/plugins/simple_captcha/gdimg.php?re=0" title="Simple CAPTCHA v1.1 by zorex" alt="[please refresh]" /></td>
<td align="left" valign="bottom">
<img src="<?php bloginfo('url'); ?>/wp-content/plugins/simple_captcha/captcha_reload.gif" onClick="setTimeout('reloadCaptcha()', 300)"
style="cursor:pointer" title="Request a new image" alt="Request a new image" />
</td>
</tr>
</table>