Why is my data getting inserted twice? PHP/MySQL
015826136@domain.com,2010-11-08 14:10:35
01DETAIL@domain.com,2011-11-01 20:14:21
01krisp10@domain.com,2010-11-08 15:00:09
01luis@domain.com,2010-11-08 15:00:09
01tthomas@domain.com,2010-11-08 15:09:13
02570734@domain.com,2011-10-10 11:44:54
02arman02@domain.com,2010-11-08 14:53:26
03091980@domain.com,2010-11-08 14:45:09
03331025@domain.com.com,2010-11-08 14:45:09

if ( isset($_POST["step"]) && $_POST["step"] == '2' ) {

    if ( isset($_FILES["file"])) {

            if ($_FILES["file"]["error"] == 0) {
                $name = $_FILES['file']['name'];
                $ext = strtolower(end(explode('.', $_FILES['file']['name'])));
                $type = $_FILES['file']['type'];
                $tmpName = $_FILES['file']['tmp_name'];

                // check the file is a csv
                if($ext === 'csv'){
                    if(($handle = fopen($tmpName, 'r')) !== FALSE) {

                        $field = $_POST['field'];
                        //clear the import table
                        mysql_query("TRUNCATE table iContact_import");

                        //loop through the CSV
                        while(($data = fgetcsv($handle, 300, ',')) !== FALSE) {
                            //$info = explode(",", $line);
                            //echo $info[0].'<br/>';
                            mysql_query("INSERT iContact_import (email,field) values ('".$data[0]."','".$field."')");
                        }

                        echo '<h3 style="color:green;">Database is prepped for new subscribers</h3>';
                        echo '<p><a href="icontact_process.php?step=3">Click here to update subscriptions</a></p>';

                    }

                } else {
                    echo '<p>File is not a CSV. Please use another field with CSV values and extension.</p>';
                }

            } else {
                echo "Error: " . $_FILES["file"]["error"] . "<br />";
            }

    } else {
        echo '<p>Please upload a CSV file with email addresses to import.</p>';
    }
}

ALTER TABLE `my_table` ADD UNIQUE KEY (`email`);