The #residualvm IRC channel on irc.freenode.net is also a good place to ask questions. Many ResidualVM developers hang out there regularly, as well as many ResidualVM users.
If you think you found a bug, take a look at our, take a look at our bug reports. Maybe a similar bug has already been filed, in which case you can add a comment to that bug report. If not, you can submit a new bug report.
There are two ResidualVM related mailing lists. One of them are for automated content only. The one where you can send emails to yourself is residualvm-devel.