mysql_num_rows(): supplied argument is not a valid MySQL result resource

<?php
include 'includes.php';
include 'includes/rotator_includes.php';
?>
<?php
if ( isset ($_POST['submit'])) {
    $problem = FALSE;
    
    if (strlen($_POST['email']) < 5) {
        $problem = TRUE;
        print '<b>ERROR: Incorrect email. Please enter valid email address. <br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
   }
  
       if (strlen($_POST['pass1']) <= 4) {
           $problem = TRUE;
     print '<b>ERROR: Your punny password is no match for the borg.  Assimilate and make it longer than 4 digits. <br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
    }
           if (strlen($_POST['fname']) < 2) {
           $problem = TRUE;
     print '<b>ERROR: Your first name seems too short or it wasn not filled in.<br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
    }
             if (strlen($_POST['lname']) < 2) {
           $problem = TRUE;
     print '<b>ERROR: Your last name seems too short or it was not filled in.<br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
    }
           if (strlen($_POST['phone']) < 9) {
           $problem = TRUE;
      print '<b>ERROR: Your phone number is too short or it wasn not filled in.  Please use your full area code when filling in your phone number.<br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
    }
    
   if (strcmp($_POST['pass1'],$_POST['pass2']) || empty($_POST['pass1']) ) {
           $problem = TRUE;
    //die ("Password does not match");
    print '<b>ERROR: You either left the password boxes empty or you did not type them the same twice.  Try again.<br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
    }
    
     if (strcmp($_POST['email'],$_POST['email2']) || empty($_POST['email']) ) {
           $problem = TRUE;
    //die ("Email not match");
    print '<b>ERROR: You either left the email boxes empty or your did not type them the same twice.  Try again.<br /><input type="button" value="Go Back and Fix It" onclick="history.back();"><br /></b>';
    }
$sql=mysql_query("SELECT * FROM users WHERE email={$_POST['email']}");
$result=mysql_query($sql);
$count=mysql_num_rows($result);
if($count==1){
           $problem = TRUE;
    //die ('ERROR: User account already exists.');
    print '<b>ERROR: User account already exists.<br /><input type="button" value="Go Back and Fix It" onclick="history.back();"></b>';
 
    }
 
if ($problem == FALSE) { 
    $query = "INSERT INTO users
                  (first_name, last_name, email, password, phone, sponsor, leg, signup_date)
                  VALUES
                  ('{$_POST['fname']}', '{$_POST['lname']}', '{$_POST['email']}', '{$_POST['password']}', '{$_POST['phone']}', '$member_number', '$leg_pref', NOW())";  
session_register("email");
session_register("password"); 
header("location:howitworks.php");
        
                  mysql_close();
} else {
    print 'You didn\'t fill out the form correctly.  Try again.';
}
}
?>
 
Welcome to <?=$sitename?>.  My name is <?=$firstname?> <?=$lastname?> and I would like to introduce you to one of the most exciting programs of all time.
<br>
<br>
Resistance is futile.  You will assimilate.  Pre-enroll now puny human slave.<br>
<form name="signup" action="index.php" method="post">
First Name <input type="text" name="fname" maxlength="20"><br><br>
Last Name <input type="text" name="lname" maxlength="35"><br><br>
Email <input type="text" name="email" maxlength="100"><br><br>
Confirm Email <input type="text" name="email2" maxlength="100"><br><br>
Password <input type="password" name="pass1" maxlength="50"><br><br> 
Confirm Password <input type="password" name="pass2" maxlength="50"><br><br> 
Phone <input type="text" name="phone" maxlength="15"><br><br>
<input type="submit" name="submit" value="Submit">
</form>