I'm afraid we broke something on your end... Changeset d8fa35c28335 in Mercurial added extra quoting to the arguments used with SSH connections. This breaks things like hg-ssh and your conq service.
When using SSH with Bitbucket I now get
% hg incoming ssh://bb/mg/hg-i18n --debug
running ssh bb ''''hg''' -R '''mg/hg-i18n''' serve --stdio'
sending hello command
sending between command
remote: conq: invalid command syntax.
abort: no suitable response from remote hg!
For comparison, the first line was
running ssh bb "hg -R mg/hg-i18n serve --stdio"
before the change.
We're also tracking this in the Mercurial bugtracker: http://mercurial.selenic.com/bts/issue2983
I'm just putting it here too so that people can find it and so that you can figure out if you want to change the conq service before we figure out what we want to do on the Mercurial side.