FAILSAFE preventing errors from displaying?

Used to, when I had an error in development mode, I saw a pretty stack trace in the browser and didn't have to go the server console, and in production mode I would see the pretty 500.html error page be displayed. Since I've started using Rails 2.2, I no longer get either of these. I get the ugly black and white "500 Internal Server Error" message. The happens the same in Mongrel for development and with Passenger in production, so I figure it has to do with some kind of configuration snafu.

In the logs I see something like     /!\ FAILSAFE /!\ Sat Jan 10 23:51:45 -0600 2009       Status: 500 Internal Server Error (followed by the error message and stack trace)

I didn't used to see anything like this, so I suspect it might have something to do with what's going on. I think this is also preventing exception_notification from performing its duties properly. Any suggestions?

Do you use rspec-rails ? I had it required in environment.rb. The problem went away when I removed "config.gem 'rspec-rails', :lib => 'spec/rails'". That's also what also prevented my exception notifications to work correctly.

Cheers !

Alexandre