These classes should be copied to you're SuperCollider extensions library in order to be used.
The PhexEnv class will not function in any version of SuperCollider other than the DEVELOPMENT version available on GitHub due to a dependency on recent changes to the EnvironmentRedirect class. It will not version in 3.6.5/6. Unfortunately you need to build this yourself.
It was last tested against the DEVELOPMENT version of SC on 8/1/2014.
For instructions on use see the included PDF.
For support please contact Tristan Strange