Kde je chyba ?

<h2>Novinky</h2>
<br>
<br>

<?php
$id = $_GET["id"];
$a = $_GET["a"];
$user = $_POST["user"];
$email = $_POST["email"];
$text = $_POST["text"];
$submit = $_POST["submit"];
if ($id==TRUE)
{
$query = mysql_query("SELECT * FROM news WHERE id = '$id'");
while ($news = mysql_fetch_array($query))
  {
  echo "<h3>".$news["title"]."</h3>  <h4>napsal: <i>".$news["author"]."</i></h4><br>".$news["text"]."<br><br>"; 
  
  }
echo "<br><h3>Komentáře</h3><br>";
$query = mysql_query("SELECT * FROM comments_news WHERE newsid = '$id'");
while ($coment = mysql_fetch_array($query))
{
echo "Předmět:".$coment["subject"]."<br>Uživatel:".$coment["user"]."<br>E-M ail:".$coment["email"]."<br><br>Text:<br>".$coment["text"]."<br>";
}
echo "<br><a href=\"?id=$id&a=addcomment\">Přidat komentář!</a>";
  if ($a=="addcomment")
  {
    echo "<br><h3>Přidat komentář</h3><form action=\"\" method=\"POST\" >Vaše jméno:<input type=\"text\" name=\"user\"><br>Váš email:<input type=\"text\" name=\"email\"><br>Text:<br><textarea rows=\"10\" cols=\"50\" name=\"text\"></textarea><br><input type=\"submit\" value=\"Odeslat\" name=\"submit\"></form>";
  }
}
else {
$query = mysql_query ("SELECT * FROM news ORDER BY id DESC LIMIT 3");
while ($news = mysql_fetch_array($query))
{
echo "<h3><a href=\"?id=".$news["id"]."\" >".$news["title"]."</a></h3>  <h4>napsal: <i>".$news["author"]."</i></h4><br>".$news["text"]."<br><br>";
}
}

if ($submit==TRUE && $user!="" && $email!="" && $text!="")
{
$query = mysql_query("INSERT INTO comments_news (newsid, subject, user, email, text ) VALUES ('$id', 'Komentář', '$user', '$email', '$text')");
  if ($query==TRUE)
  {
  echo "<script language=\"javascript\" type=\"text/javascript\">alert('Komentář byl vložen do databáze.');</script>";
  echo "<script>window.location.href=\"http://$homepage/?id=$id\";</script>"; 
  }
  else
  {
  echo "<script language=\"javascript\" type=\"text/javascript\">alert('Nepodařilo se vložit komentář.');</script>";
  echo "<h2>$db_error</h2>";
  }
}
else
{
echo "<br>Musíte vložit všechny údaje!";
}


?>