Premature end of script headers error using Rails 2.3.1 and Passenger 2.1.1

I'm getting an HTTP 500 Internal Server Error using the latest beta of Rails (2.3.1 aka 2.3 RC2) and Passenger (2.1.1) beta under Ubuntu Intrepid (8.1).

I've put the Passenger configuration files into two separate files under mods-available and I've created symbolic links from mods-enabled. The default way of the Apache configuration under Ubuntu 8.1, just like all other modules.
I am getting 'Premature end of script headers: rails, referer: ...' errors and I have no idea why this happens. It never happened before when I was using 8.04 (Hardy release)

Here's my configuration:

/etc/apache2# cat apache2.conf | grep -i mods-enabled
Include /etc/apache2/mods-enabled/*.load
Include /etc/apache2/mods-enabled/*.conf

/etc/apache2/mods-enabled# ls -la | grep passenger
lrwxrwxrwx 1 root root 32 Mar 4 22:19 passenger.conf -> ../mods-available/passenger.conf
lrwxrwxrwx 1 root root 32 Mar 4 22:19 passenger.load -> ../mods-available/passenger.load

/etc/apache2/mods-enabled# cat passenger.load
LoadModule passenger_module /opt/rubyenterprise/lib/ruby/gems/1.8/gems/passenger-2.1.1/ext/apache2/mod_passenger.so

/etc/apache2/mods-enabled# cat passenger.conf
<IfModule passenger_module>
  PassengerRoot /opt/rubyenterprise/lib/ruby/gems/1.8/gems/passenger-2.1.1
  PassengerRuby /opt/rubyenterprise/bin/ruby
  # PassengerDefaultUser www-data
</IfModule>

I've commented out the PassengerDefaultUser directive, since the whole Apache process is running under the www-data user so it doesn't seem to be necessary. However, now I'm getting the server error above.
I don't know if this is a problem with the Rails application itself (blank newly created, v 2.3.1 - aka 2.3 RC2) Rails or with Passenger 2.1.1 beta.

Any thoughts?
Cheers,
Attila

OK, i've put the configuration files into pastie since Google broke it into more lines, it think this is more readable now:
http://pastie.org/411007

Attila Györffy wrote:

I am getting 'Premature end of script headers: rails, referer: ...' errors and I have no idea why this happens.

Is this the exact error message?