Thanks to Jason Boyer of Indiana Evergreen, it was brought to my attention that if you use the recommended Apache configuration with NCIPServer, Evergreen, and OpenSRF version 2.5.0 or later, NCIPServer crashes whenever you access its URL with the following error message:
Warning caught during route execution: Use of uninitialized value in scalar assignment at /usr/local/share/perl/5.22.1/OpenSRF/DomainObject/oilsMessage.pm line 246.
The reasons are a bit arbitrary and technical. The solution, however, is simple. To correct the situation, add the following directive inside the <Location /NCIP/> block in your eg_host.conf:
PerlSetEnv DANCER_ENVIRONMENT "production"
If you're upgrading to Evergreen 2.12 and OpenSRF 2.5, then you need to add the above to your configuration. Even if you are not planning an upgrade in the near future, adding that line will not hurt anything and it will help when you do eventually upgrade. Really, that directive should have been in the recommended configuration from the start, but was ignored owing to an oversight on my part.
The README has been updated to include the addition of the above line for configuration of both Apache 2.2 and Apache 2.4.