Column count doesn't match value count at row 1

<?php else if(isset($_GET["thread_id"]) && isset($_GET["board_id"]))
{

echo'
<form action="post.php" name="message" method="post">
<table class="new">
<tr>
<td class="text">
<center>


| Fett
| Kursiv
| Unterstrichen
| Durchgestrichen
| Link
| Bild
| Code
| PHP |



<textarea name="message" style="border:1px solid black;background-color:#dcdcdc" rows="10" cols="85"></textarea>

[img]images/smilies/angry.gif[/img]
[img]images/smilies/biggrin.gif[/img]
[img]images/smilies/cry.gif[/img]
[img]images/smilies/dum.gif[/img]
[img]images/smilies/evil.gif[/img]

<a class="small" href="#" target="_blank" onclick="FensterOeffnen(this.href); return false">
Weitere Smilies...</a>


<input type="submit" name="los" value="Speichern" class="register">
<input type="hidden" name="board_id" value="'.$_GET["board_id"].'">
<input type="hidden" name="author_id" value="'.$_SESSION["user_id"].'">
<input type="hidden" name="author" value="'.$_SESSION["user_username"].'">
<input type="hidden" name="thread_id" value="'.$_GET["thread_id"].'">
</center>

</td>
<tr>
</table>

</form>
';
        
}?>

else if(isset($_POST["board_id"], $_POST["thread_id"])) {

$date = time();

  $sql1 = sprintf("INSERT INTO post (post, author_id, author, thread_id, board_id, date) VALUES ('%s', %u, '%s', %u, %u)",
    $_POST['message'], $_POST['author_id'], $_POST['author'],$_POST['thread_id'], $_POST['board_id'], $date);
  mysql_query($sql1) or die(mysql_error());

  $sql2 = sprintf("UPDATE user SET posts = posts + 1 WHERE id = %u LIMIT 1", $_POST['author_id']);
  mysql_query($sql2) or die(mysql_error());
  
$author=''.$_POST['author'].'

'.date("H:i // d.m.y", $date).'';

    $sql4 = sprintf("UPDATE board SET new_thread = 1 WHERE id = %u LIMIT 1", $_POST['board_id']);
  mysql_query($sql4) or die(mysql_error());

      $sql5 = sprintf("UPDATE thread SET new_post = 1 WHERE id = %u LIMIT 1", $_POST["thread_id"]);
  mysql_query($sql5) or die(mysql_error());

        $sql7 = "UPDATE board SET new_thread_author = '".$author."' WHERE id = '".$_POST['board_id']."'";
  mysql_query($sql7) or die(mysql_error());

        $sql6 = "UPDATE thread SET new_thread_author = '".$author."' WHERE id = '".$_POST['thread_id']."'";
  mysql_query($sql6) or die(mysql_error());
  
  header(sprintf('Location: posts.php?board_id=%u&thread_id=%u#page_end', $_POST['board_id'], $_POST['thread_id']));
  exit;
}