Crumbs this could get messy if you're unsure as to what you're doing.
Also I do apologise for creating a profile - I had to check what was going on when you log in. You seemed to have moved everything in alternate places so they're still functioning which is good.
By the way you get an error when you have successfully registered. Moving on...
1. try commenting this portion out and report your results. Hopefully it should get you a tiny bit closer...
<tr>
<td colspan="2" class="HeadLine">
<form action="{$xcart_web_dir}/include/login.php" method="post" name="toploginform">
<input type="hidden" name="mode" value="logout" />
<input type="hidden" name="redirect" value="{$redirect|escape}" />
<table cellpadding="0" cellspacing="0" width="100%">
<tr>
<td class="FLCAuthPreBox">
{if $active_modules.SnS_connector and $sns_collector_path_url ne '' && $config.SnS_connector.sns_display_button eq 'Y'}
<img src="{$ImagesDir}/rarrow.gif" alt="" valign="middle" /><b>{include file="modules/SnS_connector/button.tpl" text_link="Y"}</b>
{else}
<img src="{$ImagesDir}/spacer.gif" class="Spc" alt="" />
{/if}
</td>
{if $login ne ""}
<td align="right" nowrap="nowrap"><b>{$userinfo.firstname} {$userinfo.lastname}</b> {$lng.txt_logged_in}</td>
<td class="FLCAuthBox">
{if $js_enabled}
{include file="buttons/button.tpl" button_title=$lng.lbl_logoff href="javascript
: document.toploginform.submit();" js_to_href="Y"}
{else}
{include file="buttons/logout_menu.tpl"}
{/if}
</td>
{/if}
</tr>
</table>
</form>
</td>
</tr>