I decided to upgrade a server from lucid to precise and then upgrade airtime. I 'removed' airtime first which also removed liquidsoap and backed up Airtime's database and media.
The upgrade to precise seemed to go OK.
Then I installed airtime-easy-setup.deb followed by apt-get install airtime. Liquidsoap was installed then as well. The Airtime install was OK until liquidsoap and there it failed.
In the end I found it best to backup the database and then purge airtime, liquidsoap, monit and then use locate to find anything still hanging around and delete that too. This got my version 2.4.0 going - at least at the start.