gen~ AU Export Issues

I followed this guide: http://designingsound.org/2013/04/a-tremolo-au-plugin-with-max/

In Reaper, the AU plugin loads fine but it does not allow me to change parameter values on the component UI using my mouse. However, when I draw in data in the automation lanes, the plugin parameters work fine.

The AU component also runs in Live; I get an audio output but with a lot of artifacts in the audio. Not entirely sure why this is the case as I am having no issue with the component in Reaper, as far as audio is concerned.

Any ideas why this might be the case? Many thanks in advance.