Help: 500 error page instead of stack trace even on own machine

Hi everybody,

my problem:
Since yesterday, even running in development, and from the same
computer where the server is running, I always get the 500 error page
instead of the detailed stack trace, making debugging really hard.

solutions I've tried:
- switching servers (mongrel instead of webrick) and ports, restarting
etc
- clearing old session
- setting config.action_controller.consider_all_requests_local = true
in the development.rb config file
- even overriding some internals of ActionController

Nothing worked, any other ideas?

Could installing a plugin (paginating_find) or gem (loginGenerator)
possibly be the reason?

Thanks in advance for any help,
Elmar Schraml

(Configuration: Suse Linux , ruby 1.8.5, rails 1.1.6, radrails 0.7.1 )