[Dovecot] problem with quota

hi everyone I have dovecot 1.0.rc15-2, postfix 2.3.8 and virtual users and domains installed in debian sarge, the users quota are not working. I have applied the pacth VDA and didn't work, if a I sent a mail to another user which exceeds his quota this user can receive the mail without problem, this said to me that the quota doesn't work. I use maildir in mi configuration.

Please help me with this problem.