I'm currently coding a news section for my site (I'm using it as an excuse to learn PHP). The majority of the site is working OK, its just when I edit the news and Submit it, the following error message comes up.

Warning: Cannot modify header information - headers already sent by (output started at .../php/edit.php:1) in ..../php/edit.php on line 19
Invalid entry ID.

Here is the section of 'offending' code.

PHP Code:

 $id = htmlspecialchars(strip_tags($_POST['id']));
    $month = htmlspecialchars(strip_tags($_POST['month']));
    $date = htmlspecialchars(strip_tags($_POST['date']));
    $year = htmlspecialchars(strip_tags($_POST['year']));
    $time = htmlspecialchars(strip_tags($_POST['time']));
    $summary = htmlspecialchars(strip_tags($_POST['summary']));
    $entry = htmlspecialchars(strip_tags($_POST['entry']));
    $title = htmlspecialchars(strip_tags($_POST['title']));

    $timestamp = strtotime ($month . " " . $date . " " . $year . " " . $time);

    $result = mysql_query("UPDATE php_news SET timestamp='$timestamp', title='$title', summary='$summary', entry='$entry' WHERE id='$id' LIMIT 1") or print ("Can't update entry.<br />" . $sql . "<br />" . mysql_error());

//--->line19  
header("Location: news.php?id=" . $id);
    
} 


Make sure nothing has already been sent to the browser - any echo's, print's, or even just a space before the first <?php tag.

Thanks for that, its worked a treat.