what i notice is that you do not initiate the $errors variable before trying to concatenate values onto it..
$errors = ""; if (empty($flight)) {$errors .= "Please enter the flight number. <br />";}if (empty($dept)) {$errors .= "Please enter the departure airport. <br />";}if (empty($arrival)) {$errors .= "Please enter the arrival airport. <br />";}if ($flightTime == "") {$errors .= "Please enter the flight time. <br />";}if (empty($fuel)) {$errors .= "Please enter the fuel. <br />";}if ($errors == "") {$sql2 = "UPDATE pireps SET flight = '$flight', $dept = '$dept', arrival = '$arrival', flightTime = '$flightTime', fuel = '$fuel', aircraft = '$aircraft', status='$status' comment = '$comment' WHERE id='$id'"or die("An error has occured. Please contact the webmaster with the following error: " . mysql_error());$result2 = mysql_query($sql2);header("Location: logbook.php?pid=" . $pilotid);} else {}}