Problema a la hora de registro.

<div class="main_wrap">
<div class="top_wrap"></div>
<div id="header">
<a name="top"></a>
<div id="header_left">
<div class="logo">
<a href="$vboptions[forumhome].php$session[sessionurl_q]"><img src="$stylevar[titleimage]" border="0" alt="$vboptions[bbtitle]" /></a></div>
<div id="nav">
<ul>
<li><a class="nav_home" href="$vboptions[forumhome].php$session[sessionurl_q]"></a></li>
<if condition="$show['guest']">
<li><a class="nav_register" href="register.php$session[sessionurl_q]" rel="nofollow"></a></li>
<else />
<li><a class="nav_usercp" href="usercp.php$session[sessionurl_q]"></a></li>
</if>
<li><a class="nav_members" href="memberlist.php$session[sessionurl_q]"></a></li>
<li><a class="nav_search" href="search.php$session[sessionurl_q]"></a></li>
<if condition="$show['guest']">
<li><a class="nav_faq" href="faq.php$session[sessionurl_q]" accesskey="5"></a></li>
<else />
<li><a class="nav_logout" href="login.php?$session[sessionurl]do=logout&amp;logouthash=$bbuserinfo[logouthash]" onclick="return log_out('$vbphrase[sure_you_want_to_log_out]')"></a></li>
</if>
</ul>
</div>
</div>
<div id="header_right">
<div class="header_stats"></div>
<div class="header_right_repeat">
<div class="login_main">
<!-- breadcrumb, login, pm info -->
<table cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
<if condition="$show['member']">
    <td nowrap="nowrap">
    <div class="smallfont">
<br />
        <strong><phrase 1="$bbuserinfo[username]" 2="member.php?$session[sessionurl]u=$bbuserinfo[userid]">$vbphrase[welcome_x_link_y]</phrase></strong><br />
        <phrase 1="$pmbox[lastvisitdate]" 2="$pmbox[lastvisittime]">$vbphrase[last_visited_x_at_y]</phrase>

        <if condition="$show['notifications'] AND $show['popups']">
            <div><span id="notifications"><a href="usercp.php$session[sessionurl_q]">$vbphrase[your_notifications]:</a> <strong>$notifications_total</strong></span></div>
            <script type="text/javascript"> vBmenu.register("notifications"); </script>
        <else /><if condition="$show['pmstats']">
            <div><phrase 1="$vbphrase[unread_x_nav_compiled]" 2="$vbphrase[total_x_nav_compiled]" 3="$session[sessionurl_q]">$vbphrase[private_messages_nav]</phrase></div>
        </if></if>

        <if condition="$show['pmwarning']"><div><strong><phrase 1="$vbphrase[pmpercent_nav_compiled]">$vbphrase[your_pm_box_is_x_full]</phrase></strong></div></if>
    </div>
    </td>
<else />
    <td nowrap="nowrap" style="padding:0px">
<br />
        <!-- login form -->
        <form action="login.php?do=login" method="post" onsubmit="md5hash(vb_login_password, vb_login_md5password, vb_login_md5password_utf, $show[nopasswordempty])">
        <script type="text/javascript" src="clientscript/vbulletin_md5.js?v=$vboptions[simpleversion]"></script>
        <table cellpadding="0" cellspacing="$stylevar[formspacer]" border="0">
        <tr>
            <td class="smallfont" style="white-space: nowrap;"><label for="navbar_username">$vbphrase[username]</label></td>
            <td><input type="text" class="bginput" style="font-size: 11px" name="vb_login_username" id="navbar_username" size="10" accesskey="u" tabindex="101" value="$vbphrase[username]" onfocus="if (this.value == '$vbphrase[username]') this.value = '';" /></td>
            <td class="smallfont" nowrap="nowrap"><label for="cb_cookieuser_navbar"><input type="checkbox" name="cookieuser" value="1" tabindex="103" id="cb_cookieuser_navbar" accesskey="c" />$vbphrase[remember_me]</label></td>
        </tr>
        <tr>
            <td class="smallfont"><label for="navbar_password">$vbphrase[password]</label></td>
            <td><input type="password" class="bginput" style="font-size: 11px" name="vb_login_password" id="navbar_password" size="10" tabindex="102" /></td>
            <td><input type="submit" class="button" value="$vbphrase[log_in]" tabindex="104" title="$vbphrase[enter_username_to_login_or_register]" accesskey="s" /></td>
        </tr>
        </table>
        <input type="hidden" name="s" value="$session[sessionhash]" />
        <input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" />
        <input type="hidden" name="do" value="login" />
        <input type="hidden" name="vb_login_md5password" />
        <input type="hidden" name="vb_login_md5password_utf" />
        </form>
        <!-- / login form -->
    </td>
</if>
</tr>
</table>
<!-- / breadcrumb, login, pm info -->
</div>
</div>
</div>
</div>