Thanks for writing this up. Sadly you checkout of acs-mail-lite was not recent, this is why the incoming e-mail handling did not work there.
In general you should not have a seperate directory for incoming notification e-mails. This is too much hassle to setup.
What should be done is to make sure that notifications has a callback implementation for acs_mail_lite::incoming_email that actually works. The callback mechanism itself works just fine (since 5 days ago).
In the long run, as forums wants to achieve the following goals:
* (1) Respond to post
* (1) Starting new threads
* (2) Subscribing to forum
* (2) Unsubscribing to a forum
we should not rely on a notifications callback but write forums callbacks instead.
As an example, writing a callback for "forums-subscribe-$forum_id@" and "forums-unsubscribe-$forum_id@" is a piece of cake.
For responding to a post I would have a convention like "forums@reply-$message_id@", which is essentially what notifications does at the moment.
As for starting a new thread: I would suggest to make forums parties and allow the administrator to set an E-Mail address for the forum, instead of relying on the standard e-mail "forums-post-$forum_id". "mailto:openacs@yoursite.com"; is much easier to remember.
