Password, Dreamweaver, PHP and mysql

Dear,

I created a user registration for and encrypted the password using sha1

if ($pwdOK) {
        $_POST['pwd'] = sha1($_POST['pwd']);
    }

and for the login I used, this line of code right after the connection line to recognize the encrypted pwd as Dreamweaver doesn't do it on its own

if (isset($_POST['pwd'])) { $_POST['pwd'] = sha1($_POST['pwd']);}

but surprisingly, it is not working, I am being redirect to the error page instead, even though I am using both right user and password.

Any one, has any idea how I can possibly solve this problem.

Romeo