Counting MySQL rows not working

[Anon]

Hey

Im trying to use the following code to see if a user exists in my table:

Function CheckUser($input_user){
GLOBAL $hostname,$username,$password,$dbname,$root;

mydbconnect($hostname,$username,$password,$dbname);
	$query = "SELECT * FROM Users WHERE User=Ben";
	$result = MYSQL_QUERY($query);
	$count = MYSQL_NUM_ROWS($result);

IF($count){
	MYSQL_CLOSE();
	CheckPass($input_user);		
}else{
	MYSQL_CLOSE();
	Header("Location: $root/login.php?error=$input_user");		

}

}

All it returns is:
Warning: Supplied argument is not a valid MySQL result resource in /usr/local/apache/htdocs/dev/checklogin.php

[factory21]

You need single quotes around \"Ben\" in your query.

It helps to check the result returned from mysql_query and to use the mysql_error() function to get the error if the result is null (false).