not sure why I get this error on form process page

[webguync]

The error is "Error: Duplicate entry '' for key 'usr'"

 

I don't have any fields with that name.

 

here is the process code.

 

<?php
$con = mysql_connect("localhost","uname","pw") or die('Could not connect: ' . mysql_error());
mysql_select_db("db") or die(mysql_error());

$FirstName=mysql_real_escape_string($_POST['FirstName']); //This value has to be the same as in the HTML form file
$LastName=mysql_real_escape_string($_POST['LastName']); //This value has to be the same as in the HTML form file
$UserName=mysql_real_escape_string($_POST['UserName']); //This value has to be the same as in the HTML form file
$Password= md5($_POST['Password']); //This value has to be the same as in the HTML form file
$email=mysql_real_escape_string($_POST['email']); //This value has to be the same as in the HTML form file
$Zip=mysql_real_escape_string($_POST['Zip']); //This value has to be the same as in the HTML form file
$Birthday=mysql_real_escape_string($_POST['Birthday']); //This value has to be the same as in the HTML form file
$Security=mysql_real_escape_string($_POST['Security']); //This value has to be the same as in the HTML form file
/*
*  Specify the field names that are in the form. This is meant 
*  for security so that someone can't send whatever they want 
*  to the form.
*/
$allowedFields = array(
'FirstName',
'LastName',
'UserName',
'Password',
'email',
'Birthday',
'Zip',
'Security',
);

// Specify the field names that you want to require...
$requiredFields = array(
'FirstName',
'LastName',
'UserName',
'Password',
'email',
'Birthday',
'Zip',
'Security',
);

$errors = array();
foreach($_POST AS $key => $value)
{
// first need to make sure this is an allowed field
if(in_array($key, $allowedFields))
{
	$$key = $value;

	// is this a required field?
	if(in_array($key, $requiredFields) && $value == '')	
	{
		$errors[] = "The field $key is required.";
	}
}	
}

// were there any errors?
if(count($errors) > 0)
{
$errorString = '<p>There was an error processing the form.</p>';
$errorString .= '<ul>';
foreach($errors as $error)
{
	$errorString .= "<li>$error</li>";
}
$errorString .= '</ul>';

// display the previous form
include 'index.php';
}
else
{


$sql="INSERT INTO Profile (`FirstName`,`LastName`,`Username`,`Password`,`email`,`Zip`,`Birthday`,`Security`) VALUES ('$FirstName','$LastName','$UserName','$Password','$email','$Zip','$Birthday','$Security')"; 
if (!mysql_query($sql,$con)) {
die('Error: ' . mysql_error());
}
//send email
mail('email@gmail.com','A profile has been submitted!',$FirstName.' has submitted their profile',$body);

// display the thank you page
header("Location: thanks.html");
}