Thanks, Dagon. When I made the changes you suggested, I get this error: unexpected T_ENCAPSED_AND_WHITESPACE, expecting T_STRING or T_VARIABLE or T_NUM_STRING.
I'm posting the whole query so you can see what I'm trying to do.
$query = "UPDATE posts SET employer='". $POST['employer'] . "',
email ='". $POST['email'] . "',
pass ='". $POST['pass'] . "',
if($FILES['image']['name'] !=''){
picture= '".$FILES['image']['name'] . "',
}
first ='". $POST['first'] . "',
last ='". $POST['last'] . "',
phone ='". $POST['phone'] . "',
web ='". $POST['web'] . "',
address ='". $POST['address'] . "',
city ='". $POST['city'] . "',
state ='". $POST['state'] . "',
zip ='". $POST['zip'] . "',
days ='". $POST['days'] . "',
comment ='". $POST['comment'] . "'
WHERE email = '". $POST['email'] . "' AND pass = '". $_POST['pass'] . "'";
$result = mysql_query($query) or die ("<p>Errpr : " . mysql_error());
header("Location: index.php");
}