Reisnstalling the sasl stuff from the ubuntu howto was not a good idea, we nare now more far away from a solution then a few poats agi
Its always a bad idea to mix dirrenet howtos, this will most likely result in a non working setup.
1) Reconfigure the complete postfix stuff with the steps described in the debian setup.
2) Install the courier packages as described in the debian setup.
3) Send a email to a local mailbox from a webmail package on your server, e.g. uebimiau and post the lines that you get in the logfile.
Maildir must be enabled.