> Check the permissions on your log directory and log file and make sure 
> that the www-data user (or whatever apache runs as) can write to those 
> directories.
>
> This stymied me for a while as well.

This has been one of the top "stymizers" for people and a constant 
source of questions on #rubyonrails. I'll make sure to rectify this 
shortly! An obscure and untraceable error for something that should be 
very simple. Bad Rails, Baaaad Rails! ;)
--
David Heinemeier Hansson,
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http://www.loudthinking.com/ -- Broadcasting Brain
http://www.nextangle.com/    -- Development & Consulting Services