folders subcribe doesn't work with mozilla 0.9.x and Cyrus IMAP

[SaGu]

Hello,
        I'm using mozilla 0.9.3 as mail client for my IMAP mailbox on Cyrus-IMAPD 
2.0.14. But folders subcribe/unsubscribe does not work. Does anybody has 
any comments ?

Thanks anyway

Saulius