If you install any recent version of OpenStudio, you will get the SketchUp plugin and Radiance installed as well, automatically. It sounds like you've done that, and are getting a simulation failure when trying to run OpenStudio on a model with the Radiance measure. Is that correct? If there is no further information besides "failed", please have a look in your model's run directory for the stdout and stderr files and see what those reveal. There may be a more conclusive error in one of those two files.