Section B.111, “LuxRenderEngine” renders images by executing the "luxconsole" command (note: lower-case). This should work out-of-the-box on GNU/Linux and Windows. On MacOSX, the luxconsole executable is distributed in an application bundle which the user could put anywhere. In this case, you will either have to adjust your PATH to point to the interior of the bundle, or create a shell script wrapper to start the render engine, something along the lines of:
#!/bin/sh cd /Applications/LuxRender.app/Contents/MacOS ./luxrender $*