cyrus imap does not work after upgrade II

["Daniel Fabian" <daniel.fabian@fh-hagenberg.at>]

Hi List,

First of all, sorry for posting this question again. I know it has been
asked yesterday, but as I can't login to get my mails, I can't answer in the
according thread. Anyway, I have exactly the same problem as the user who
previously asked: After the upgrade yesterday whenever I try to login to my
cyrus imapd, I find the following error in my logfiles:

Oct 28 18:08:03 server cyrus/master[22011]: about to exec
/usr/lib/cyrus/bin/imapd
Oct 28 18:08:03 server cyrus/imapd[22011]: telling master 2
Oct 28 18:08:03 server cyrus/imapd[22011]: accepted connection
Oct 28 18:08:03 server cyrus/imapd[22011]: telling master 3
Oct 28 18:08:06 server cyrus/imapd[22011]: could not find auxprop plugin,
was searching for '[all]'
Oct 28 18:08:06 server cyrus/imapd[22011]: could not find auxprop plugin,
was searching for '[all]'
Oct 28 18:08:06 server cyrus/imapd[22011]: badlogin: localhost[127.0.0.1]
plaintext cyrus SASL(-13): user not found: checkpass failed
Oct 28 18:08:09 server cyrus/imapd[22011]: telling master 1
Oct 28 18:09:09 server cyrus/imapd[22011]: telling master 2

Before the upgrade, it worked just fine. Now someone answered that you have
to downgrade sasl2, but as I'm relativly new to debian, I don't know how to
do that. I found an archive libsasl2-modules_2.1.7-3_i386.deb in
/var/cache/apt/archives and installed it with dpkg -i
libsasl2-modules_2.1.7-3_i386.deb but it still does not work.

Could someone please tell me, why it won't work anymore?

Thanks in advance,
Daniel