IOError when starting Passenger

[Drew]

I've just updated the following gems, (from version -> to version):

passenger: 2.0.6 -> 2.2.4
sinatra: 0.9.1.1 -> 0.9.2
rack: 0.9.1 -> 1.0.0
rack-cache: 0.4 -> 0.5

I've also updated the passenger apache module. I can't get my
application to start any more. I get the following error:

*** Exception IOError in PhusionPassenger::Rack::ApplicationSpawner
(not opened for reading) (process 30862):
from /usr/lib/ruby/1.8/delegate.rb:297:in `read'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/utils.rb:236:in `report_app_init_status'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/rack/application_spawner.rb:91:in `run'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/rack/application_spawner.rb:69:in
`spawn_application'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/utils.rb:182:in `safe_fork'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/rack/application_spawner.rb:62:in
`spawn_application'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/rack/application_spawner.rb:45:in
`spawn_application'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/spawn_manager.rb:158:in `spawn_application'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/spawn_manager.rb:286:in `handle_spawn_application'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/abstract_server.rb:351:in `__send__'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/abstract_server.rb:351:in `main_loop'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/lib/
phusion_passenger/abstract_server.rb:195:in `start_synchronously'
from /usr/lib/ruby/gems/1.8/gems/passenger-2.2.4/bin/passenger-spawn-
server:61


Has anyone seen this before? I've dipped in to the passenger code, and
it looks as though the IOError occurs when attempting to write to a
temporary file. I can't make any sense of it beyond that though.

Any pointers would be greatly appreciated.

Thanks,
Drew