problems setting up lightwork (no functions)

Hello, 

I'm using moodle 2.4, and trying to set up lightwork . When I following the instructions here: http://docs.moodle.org/dev/Lightwork under Administraiton and Configuration, I am able to get so far as setting up the Lightwork service, but I can't do the last step of adding the lightwork functions to the program.   Is there something I should install that I haven't or some trick I'm missing?

I'm using the release version of 2.4

Thanks,

Eric O