JRuby on Rails db:test:purge fails! Need help

My system is:
Ubuntu 10.04, JRuby 1.6.7, Ruby on Rails 3.0.9,
activerecord-jdbc-adapter 1.2.2, activerecord-jdbcderby-adapter

Up until a few days ago, “rake test:units” was working fine, but now
suddenly it fails with the following message:

Task not supported by ‘jdbc’ <<–same msg for ‘jdbcsqlite3’ and ‘derby’

Tasks: TOP => db:test:load => db:test:purge

I tried this using derby, jdbcsqlite and jdbc, all fail with the same
message. I assume it is environment related, as the same code in another
Ubuntu machine (11.10) runs just fine. I compared gem versions and they
are the same in both machines.

Has anyone faced this problem before and can suggest a solution or