Thanks for the message.
My problem is that I need to use 1.8.5 for compatibility with an
existing project. We have been running 1.8.5 for some time. I
installed rvm so that we could retain the 1.8.5 project whilst
developing a new project with the latest Ruby. We were able to install
all of the gems required for the old project, prior to using rvm. I
got the ENV_PATHS error when trying to build a duplicate 1.8.5 setup,
with the same gems, inside of rvm. So, the problem has something to do
with how rvm and/or the 1.8.5 version of ruby inside of rvm are
configured. The docs for the Gem::Installer class say that ENV_PATHS
is supposed to point to where env might live, as explained here:
http://slimgems.github.com/docs/Gem/Installer.html.