variabel "forsvinder"

Jeg har stirret mig blind på min kode.. jeg har et id-nummer ($id) som sættes i starten af dokumentet... men variablen "forsvinder" når jeg kommer ind i if($submit).. sætningen - nogen der kan hjælpe mig henad mod en løsning?

<?php
    include ("dbconnect.php");
    $id=$HTTP_GET_VARS["id"];

    $query = mysql_query("SELECT * FROM `cns-dvd` WHERE id='$id'");

    while($r = mysql_fetch_array($query))
    {   
        $title = $r["title"];
        $org_title = $r["org_title"];
        $region = $r["region"];
        $picture = $r["picture"];
        $director = $r["director"];
        $production_year = $r["production_year"];
        $running_time = $r["running_time"];
        $video_format = $r["video_format"];
        $actor = $r["actor"];
        $rating = $r["rating"];
        $discs = $r["discs"];
    }


    echo '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head>
        <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
        <meta http-equiv="Content-Language" content="dk-da">
        <title>CNS DVD List</title>
        <Link rel="stylesheet" Type="text/css" href="cns.css">
        </head>';


    echo "<form name=\"editdvd\" style=\"margin-bottom:0; margin-top:0;\" action=\"" . $PHP_SELF . "\" method=\"post\">

          <table width=\"100%\"><tr><td width=\"150\"><b>Title:</b>
          </td><td width=\"*\"><input type=\"text\" name=\"title\" size=\"50\" value=\"$title\">
          </td></tr><tr><td width=\"150\"><b>Original Title:</b>
          </td><td width=\"*\"><input type=\"text\" name=\"org_title\" size=\"50\" value=\"$org_title\">
          </td></tr><tr><td width=\"150\"><b>Region:</b>
          </td><td width=\"*\"><select name=\"region\">
            <option value=\"0\" ";

    if ($region == 0) echo "selected";
    echo ">0 - Worldwide</option>
            <option value=\"1\" ";

    if ($region == 1) echo "selected";
    echo ">1 - USA & Canada</option>
            <option value=\"2\" ";

    if ($region == 2) echo "selected";
    echo ">2 - Europe & Japan</option>
            <option value=\"3\" ";

    if ($region == 3) echo "selected";
    echo ">3 - Asia</option>
            <option value=\"4\" ";

    if ($region == 4) echo "selected";
    echo ">4 - Australia</option>
            <option value=\"5\" ";

    if ($region == 5) echo "selected";
    echo ">5 - Africa</option>
          </select> <select name=\"picture\">
            <option value=\"1\" ";

    if ($picture == 1) echo "selected";
    echo ">PAL</option>
            <option value=\"1\" ";

    if ($picture == 2) echo "selected";
    echo ">NTSC</option>
          </select>

          </td></tr><tr><td width=\"150\"><b>Video format:</b>
          </td><td width=\"*\"><select name=\"video_format\">";

    $query2 = mysql_query("SELECT * FROM `cns-format`");
    while ($r = mysql_fetch_array($query2))
    {
        echo "<option value=\"" . $r["id"] . "\" ";
        if ($video_format == $r["id"])
            echo "selected";

        echo ">" . $r["format"] . " " . $r["description"] . "</option>";
    }

    echo "</select>
          </td></tr><tr><td width=\"150\"><b>Number of discs:</b>
          </td><td width=\"*\"><input type=\"text\" name=\"discs\" size=\"4\" maxlength=\"4\" value=\"$discs\">
          </td></tr><tr><td width=\"150\"><b>Production year:</b>
          </td><td width=\"*\"><input type=\"text\" name=\"production_year\" size=\"4\" maxlength=\"4\"

value=\"$production_year\">
          </td></tr><tr><td width=\"150\"><b>Running time:</b>
          </td><td width=\"*\"><input type=\"text\" name=\"running_time\" size=\"4\" maxlength=\"4\"

value=\"$running_time\"> min.

          </td></tr></table><br>";

    echo "<input type=\"submit\" name=\"submit\" value=\"Submit\"></form>";

    if ($submit)
    {
        $finalquery = "UPDATE `cns-dvd` SET `region` = '$region', `picture` = '$picture', `title` = '$title',

`org_title` = '$org_title', `running_time` = '$running_time', `discs` = '$discs', `video_format` = '$video_format',

`production_year` = '$production_year' WHERE `id` = '$id'";

        mysql_query($finalquery);
        echo "descr: $finalquery";
    }
/*
    echo "<a href=\"editaudio.php?id=$id\" target=\"bottom\">Audio</a><br>
          <a href=\"editsubs.php?id=$id\" target=\"bottom\">Subtitles</a><br>
          <a href=\"editdirector.php?id=$id\" target=\"bottom\">Director</a><br>
          <a href=\"editcast.php?id=$id\" target=\"bottom\">Cast</a><br>";
*/
    echo "</html>";
?>

/Christian