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

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 !