i using php to delete file, but i got table loop like this:

    <table border="0" width="100%" cellpadding="0" cellspacing="0" id="product-table">
                <tr class="bg_tableheader">
                    <th class="table-header-check"><a id="toggle-all" ></a> </th>
                    <th class="table-header-check"><a href="#"><font color="white">Username</font></a>  </th>
                    <th class="table-header-check"><a href="#"><font color="white">First Name</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Last Name</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Email</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Group</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Birthday</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Gender</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Age</font></a></th>
                    <th class="table-header-check"><a href="#"><font color="white">Country</font></a></th>
                </tr>
                <?php
        $files = glob('users/*.xml');
        foreach($files as $file){
            $xml = new SimpleXMLElement($file, 0, true);
            echo '
                <tr>
                    <td></td>
                    <form action="" method="post">
                    <td class="alternate-row1"><input type="radio" name="file_name" value="'. basename($file, '.xml') .'" />'. basename($file, '.xml') .'</td>
                    <td>'. $xml->name .'&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp</td>
                    <td class="alternate-row1">'. $xml->lastname .'</td>
                    <td>'. $xml->email .'</td>
                    <td class="alternate-row1">'. $xml->level .'</td>
                    <td>'. $xml->birthday .'</td>
                    <td class="alternate-row1">'. $xml->gender .'</td>
                    <td>'. $xml->age .'</td>
                    <td class="alternate-row1">'. $xml->country .'</td>
                </tr>';
                    }
        ?>
                </table>
            </div>
<?php
if(isset($_POST['file_name'])){
    unlink('users/'.$_POST['file_name']);
}
?>
    <input type="submit" value="Delete" />
    </form>

so as you can see i got radio value set has basename (xml file name) but from some reason it not working, any idea why is that?

Thanks in advance.