The most important fix included in 0.3.0 is:

[#3586] Works OK first request, error on reload

http://rubyforge.org/tracker/index.php?func=detail&aid=3586&group_id=1201&atid=4729

that was caused by Rails' development config behavior where it reloads ActiveRecord::Base subclasses at certain times to "refresh" the class and pick up any changes you might be making during dev (keeps you from having to constantly restart webrick).

The problem is that ASF was not aware of this and only augmented the AR class the first time it gets a request to do so - along comes Rails autoreload and - wack - our bits are gone.

Hard to find - easy to fix. This is the root cause for a number of weird behaviors we have seen over the past few weeks where you get sporadic NoMethodErrors.

Fix is in activerecord-0.3.0.gem