[Dovecot] Strange and sudden deletion of mails messages

Hello everyone,

I'm having a bizarre problem (bug?) concerning deletion of messages from one of the mailboxes. The platform is set up as follows:

FreeBSD 7-STABLE Postfix 2.6-20080411 Dovecot 1.0.13 Webmail using RoundCube 0.1-STABLE

The trace (in Postfox logs) revealed that the message has been actually received, and saved to maildir, and then viewed once in Webmail. Hitting Reply in Webmail produced an error, and the letter (somehow) was nowhere to be found on the server! I have no clue what's the cause of this.

Is there a way in Dovecot to catch all commands sent to the server, thus revealing who in effect deleted the message?

Thanks in advance.

Noor