[PHP]some experienced advice on this script

Everything works fine, but I'm still new to php and was looking on feedback as to structure and form, or any errors, omissions, etc. I may have made.

Code:

---

<?php

require_once("header.php");
valid_login(0);

function do_unstuck(){
global $dbhost,$dbuser,$dbpass,$acct_db,$char_db,$user_name;

 if (empty($_POST['char'])) {
  header("Location: char_unstuck.php?error=1");
  exit();
 }
 
 mysql_connect($dbhost,$dbuser,$dbpass) or die(error("Error - Connection to database is not established !"));
 mysql_select_db($acct_db) or die(error("Error - Can't open the database ! ('$acct_db')"));
 
 $sql = "SELECT acct FROM accounts WHERE login = '$user_name'";
 $result = mysql_query($sql) or die(error(mysql_error()));
 $id = mysql_result ($result, 0, 'acct');
 $numrows = mysql_num_rows($result);
 
    if ($numrows == 0) {
      mysql_close();
      header("Location: char_unstuck.php?error=5");
            exit();
    }
 
 $char = quote_smart($_POST['char']);

 mysql_select_db($char_db) or die(error("Error - Can't open the database ! ('$char_db')"));

 $query = "SELECT acct FROM characters WHERE name = '$char'";
 $res = mysql_query($query) or die(error(mysql_error()));
 $numrow = mysql_num_rows($res);
 
 if ($numrow != 1) {
    mysql_close();
      header("Location: char_unstuck.php?error=1");
            exit();
    }
   
 $acct = mysql_result ($res, 0, 'acct');

 if ($id != $acct){
    mysql_close();
    header("Location: char_unstuck.php?error=4");
            exit();
  } else {
    $sql = "UPDATE characters SET positionX = bindpositionX, positionY = bindpositionY, positionZ = bindpositionZ, mapId = bindmapId, zoneId = bindzoneId WHERE name = '$char'";
    $result = mysql_query($sql) or die(error(mysql_error()));
  }
 
    if ($result) {
      mysql_close();
        header("Location: char_unstuck.php?error=2");
            exit();
    }
}

function unstuck(){
global $output;
 $output .= "
<center>
<fieldset style=\"width: 550px;\">
    <legend>Unstuck</legend>
  <form method=\"POST\" action=\"char_unstuck.php?action=do_unstuck\">
  <table cellpadding=\"3\" cellspacing=\"0\" border=\"0\">
      <tr align=\"left\">
      <td>
            <div class=\"large\">Character:</div>
          <input type=\"character\" name=\"char\" size=\"29\" maxlength=\"25\" />
          <input type=\"submit\" value=\"Execute\" onmouseover=\"this.className='mouseover'\" onmouseout=\"this.className=''\" /><br/>
      </td>
      </tr>
  </table>
  </form><br/></fieldset><br/><br/>
</center>";
}

if(isset($_GET['error'])) $err = $_GET['error'];
    else $err = NULL;

$output .= "<div class=\"top\">";
switch ($err) {
case 1:
  $output .=  "<h1><font class=\"error\">You did not input a valid character name!</font></h1>";
  break;
case 2:
  $output .=  "<h1><font class=\"error\">Character successfully unstuck!</font></h1>";
  break;
case 4:
  $output .=  "<h1><font class=\"error\">That character does not belong to your account!</font></h1>";
  break;
case 5:
  $output .=  "<h1><font class=\"error\">Error in selecting an account!</font></h1>";
  break;
default: //no error
    $output .=  "<h1>Enter your character name:</h1>";
}
$output .= "</div>";

if(isset($_GET['action'])) $action = $_GET['action'];
    else $action = NULL;

switch ($action){
case "do_unstuck":
  do_unstuck();
  break;
default:
    unstuck();
}

require_once("footer.php");
?>

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Seems alright, but NEVER show the MySQL error to the users, as this will give information about the db -> hackers like that.

PS: Why do you set a variable and use it immediatly with no further use later on?

$sql = "UPDATE characters SET positionX = bindpositionX, positionY = bindpositionY, positionZ = bindpositionZ, mapId = bindmapId, zoneId = bindzoneId WHERE name = '$char'";
$result = mysql_query($sql) or die(error(mysql_error()));

I mean...the $sql variable only takes more memory...

And its adviced to put all function in one file and include that, or put all function on top of the file but not between the code...
And it would be nice if you made/download a DB class, as these will handle error automatically etc, and are just shorter in code of use -> shorter code = better overview.

PPS: it's not really allowed to just dump your code here and let other go through a whole lot of code. Next time post a problem and the relevant code ;). I will let this go for this time...

ok, sorry for that, I was just looking for some help in improving my scripting, and you've given me lots to learn
thank you, I will remember to only post my errors