Need PHP Help Part II

[adm]

So its a techtuts usersystem and yet it still doesn't work...

[Heinous]

where this:

// the above line checks to see if the html form has been submitted 
$username = $_POST[username]; 
$password = $_POST[pass]; 
$cpassword = $_POST[cpass]; 
$email = $_POST[emai1]; 
//the above lines set variables with the user submitted information 
if($username==NULL|$password==NULL|$cpassword==NULL|$email==NULL|$checkbox==FALSE) { 
//checks to make sure no fields were left blank 
echo "A field was left blank."; 

remove:
|$checkbox==FALSE