How to verify two different fields using php and my sql ?

I must admit i am relatively new to php $ mysql. Please some suggest me, i want to check for the duplicate entry on my database for two fields usernae and email. My code is executing perfectely for username but not for email . I am not using any primary or unique key on both of them. Below are teh codes :

The one that is working for username :
/**
* Returns true if the username has been taken
* by another user, false otherwise.
*/
function usernameTaken($username){
global $conn;
if(!get_magic_quotes_gpc()){
$username = addslashes($username);
}
$q = "select username from users where username = '$username'";
$result = mysql_query($q,$conn);
return (mysql_numrows($result) > 0);
}

And the below for Email check doenn't work :

/**
* Returns true if the E-Mail has been taken
* by another user, false otherwise.
*/

function emailTaken($email){
global $conn;
if(!get_magic_quotes_gpc()){
$email = addslashes($email);
}
$q = "select E-Mail from users where E-Mail = '$email'";
$result = mysql_query($q,$conn);
return (mysql_numrows($result) > 0);
}

Warning that is flashed out for email is :
Warning: mysql_numrows(): supplied argument is not a valid MySQL result resource in c:\wamp\www\user\register.php on line 31

Please some one suggest me with the code or modifications.

Thanks is advance.

 

Try adding backquotes around the field name:
"SELECT `E-Mail` FROM users WHERE `E-Mail` = '$email'";