Strange behavour MY IMAP Cyrus Server

[tsg]

Hi  all!
I installed Cyrus IMAP v 2.1.9 with Cyrus SASL 2.1.7. Autentification via 
saslauthd/LDAP. Everything is OK excert one strange thing:
it looking for user.seen abd user.sub files in directory /var/imap/user with A 
CAPITAL letters, for example: /var/imap/user/T/<user>.sub. 
When script tools/mkimap makes this directory full of subdirectories with 
named with SMALL letters from 'a' to 'z'. If I make subdirectoryes with 
CAPITAL letters manually, everythng begins OK.

Please help!
sergios