Redmine

I cannot get it to run with SELinux enabled

You provide a whole lot of information, which is good, but: What's the actual error message? Please post an excerpt of the apache error log or redmines production log.

What are your rails and ruby versions?

Any specific reason you use the old 2.0.3 (2012-06-18) instead of a recent version?

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Unable to start the Phusion Passenger watchdog (/usr/lib/ruby/gems/1.8/gems/passenger-4.0.20/buildout/agents/PassengerWatchdog): Permission denied (errno=13)

Google "Unable to start the Phusion Passenger watchdog SELINUX"...
Perhaps it's something like this: http://stackoverflow.com/questions/11420572/passenger-unable-to-start-phusion

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Well, this doesn't seem to be a redmine issue, perhaps an SELinux expert may be able to get passenger up and running...