Cyrus Imap refuses to work with vpopmail maildir

[System]

Hello All,

This is my first post to the list.
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.