I imported a dump, and set the DBDefs Replication type to RT_SLAVE.
I currently have no data in my replication_control table (due to a semi-failed import), and so get this error if I visit the front page of my server:

Error:

Caught exception in MusicBrainz::Server::Controller::Root->begin "stash takes a hash or hashref at /home/musicbrainz/perl5/lib/perl5/x86_64-linux-gnu-thread-multi/Class/MOP/Method/Wrapped.pm line 162."
Stack trace:
line 301 MusicBrainz::Server::Controller::Root

I'm not sure if this should be considered a real error though, since I didn't have a complete database imported.