If you've been using the Zend Framework on a Windows platform (running IIS as the web server) and have been getting some 500 errors and have been left lacking the detail you need on the problem, you should read this new post from Rob Allen about an IIS setting that can help you out.
One of the dangers of frameworks in general is that you forget that they do lots of handy things for you. [...] The error handler in ZF will catch any exceptions and route them to the error action in the error controller. This then sets the correct HTTP response code, logs the error and optionally displays it if a config setting is set.
IIS shows you some default error pages when something goes wrong, but sometimes you might need a bit more information. Rob points you to the "Edit Error Pages Settings" panel in the IIS setup and which setting to change it to for development versus production environments.