problem imap_headerinfo

 I get a *Catchable fatal error*: Object of class stdClass could not be 
converted to string  on this line  $mail_head = imap_headerinfo($conn, $i);
if I remove it it works fine what would be casing this I really need to 
read the header. I am using php version  5.2.5

$conn = @imap_open("{" . $bouncer['host'] . ":" . $bouncer['port'] . "/" 
. $bouncer['mailtype'] . "/notls}" . $bouncer['mailbox'], 
$bouncer['username'], $bouncer['password']);
     $headers = @imap_headers($conn);
        if ($headers) {
          $email_count = sizeof($headers);
          for($i = 1; $i <= $email_count; $i++) {
               # Check the body against all saved patterns
               $mail_head = imap_headerinfo($conn, $i);     
               $mail_body = imap_fetchbody($conn, $i, 1);
                echo "mail head: $mail_head<br>\n";
                echo "mail body: $mail_body<br>\n";