PHP Fatal error with an attachment

Hi,

I installed roundcube version rc1. After the configuration of main.inc.php, db.inc.php, .htaccess and php.ini, I tried to send an email with an attachment bigger than 2MB but it doesn't work. The error message is the following :

PHP Fatal error: Allowed memory size of 16777216 bytes exhausted (tried to allocate 6321677 bytes) in /var/www/roundcube/program/lib/Mail/mimePart.php on line 283

I checked my configuration using the phpinfo() function. upload_max_size, post_max_size and memory_limit are set to 16M.

Do you have any suggestions to solve my problem?

Sincerely,

Renaud Hager