Well, I have spoken with Clickview and the law sits like this:
If you have an ERA+ license and the movie you want to show has been aired on any channel, then you can upload your own, school bought DVD version to the clickview server. In his words "After a few months, almost all movies have been aired on one channel or another, it's just new releases you won't be able to use".
Obviously this is in the context of a classroom, and if you wanted to use it for a film club or extra curricular license, then you would need to apply for the appropriate license.
Pete