Cyrus Imap refuses to work with vpopmail maildir

[System]

 Hello All,

 RedHat 7.3
 Apache 1.3.27
 PHP 4.3.1
 Qmail
 SquirrelMail 1.0.4
 qmailadmin 1.0.20
 vpopmail 5.3.20
 Cyrus Imap.
 The above is my setup.

 I have created mail accounts for my virtual domain with vpopmail and they
 are working fine with QmailAdmin.
When i try to login to SquirrelMail which is on SSL and uses Cyrus Imap
 server It simply Says "Incorrect Username/Password".
 I have checked the username and passwd they are perfectly correct and i can
 login with the same to qmail admin.
 Here i want to mark a point that these mail accounts are created with
 vpopmail and are in MailDir format. How how do i enable the working of my
 mail accounts with Cyrus ?

 Please put me on a correct path, i have searched and googled around but was
 unable to get what i want.

 Regards,
 Tina.