[PHP] mcrypt don't work.

[francesco]

Hi all,
I have problem with mcrypt function.
There is always an error that I don't know how to correct this.
This is my code:

$string = "Text string";
$key= "My key";
$encrypted = mcrypt_cfb(MCRYPT_RIJNDAEL-256, $key, $string, MCRYPT_ENCRYPT);  
echo"stringa cifrata= $encrypted";
$key = "My key";
$string = mcrypt_cfb(MCRYPT_RIJNDAEL-256, $key, $encrypted, MCRYPT_DECRYPT);  
echo"stringa decifrata= $string";

And the errore message is

Warning: mcrypt_cfb(): Module initialization failed in 
/web/htdocs/www.automationsoft.biz/home/critto.php on line 55
stringa cifrata= 
Warning: mcrypt_cfb(): Module initialization failed in 
/web/htdocs/www.automationsoft.biz/home/critto.php on line 58
stringa decifrata= 

I see, with phpinfo(), that my server support mcrypt and  RIJNDAEL-256.
I don't know why there is this error message.
All helps are precious.
Thanks in advance 
Francesco
[EMAIL PROTECTED]
(P.S. this is the link for a view in real time of  the problem 
www.automationsoft.biz/critto.php)