PHP and Cyrus problem

["Emerson Virti" <emerson.virti@xxxxxxxxx>]

Hello,
My company have almost ten thousand mailboxes on Cyrus Imap.
We use Thunderbird for IMAP client and PHP for webmail.
We have a problem in a very few mailboxes. This boxes don't have any visible
problem with Thunderbird access but in PHP, the (webmail) access provide a
"segmentation failed".
If I modify the cyrus.header file the "segmentation failed" problem is
resolved.

This is a problematic cyrus.header:
¡^B<8b>^MCyrus mailbox header
"The best thing about this system was that it had lots of goals."
        --Jim Morris on Andrew
user.0240169xxxx        5bc4b7c0488731c8
0240169xxxx     lrswipcda        $Forwarded $label1 $label4 $label2 $label3
$label5 $MDNSent NonJunk acade acgap alfredo andre_porto carneiro chevalier
cida-bruno cida_coutinho claudia concei&aoca4w-o daniela elaine erlan
fazer_reuni&aom-o fernanda godinho helenac inah joao_almeida katia lm luis
mara marcio_rfb marco maria_lucia_-_acbsa nelicio pc pendente plinio pp
resolvido rwagner tema vinicius-oracle
0240169xxxx     lrswipcda

If I modify cyrus.header, the "segmentation failed" is resolved, but this
generate a Thunderbird labels messages problem.

Modified cyrus.header:
¡^B<8b>^MCyrus mailbox header
"The best thing about this system was that it had lots of goals."
        --Jim Morris on Andrew
user.0240169xxxx        5bc4b7c0488731c8
0240169xxxx     lrswipcda        $Forwarded $label1 $label4 $label2 $label3
$label5 $MDNSent NonJunk
0240169xxxx     lrswipcda

Thunderbird version: 2.0.0.14;
PHP version (Debian Etch): 5.2.0-8+etch7
Cyrus Impad version: cyrus-imapd-2.2.12-8.1.RHEL4

I use this simple php script for tests:
<?php
$mbox = imap_open("{myserver:143/notls}INBOX", "0240169xxxx", "password") or
die("can't connect: " . imap_last_error());
      $list = imap_list($mbox, "{myserver:143}INBOX", "*");
     if (is_array($list)) {
        foreach ($list as $val) {
           echo imap_utf7_decode($val) . "\n";
                      }
              } else {
          echo "imap_list failed: " . imap_last_error() . "\n";
          }
          imap_close($mbox);
?>
If the cyrus.header file is the problematic one, the result of this script
is a list os subfolders and a "segmentation failed".

Where is the problem?

Thanks.

-- 
Émerson Salvadori Virti
emerson.virti@xxxxxxxxx