Public showings of copyrighted films always need to go through the rightful
owners or their distributors. GATT doesn't change or alter that, just the
number of titles that fall under that law. And if you use the music scores on
the Kino tapes you would have to get their permission to use those (I'm sure
Jessica would be kind about that) as well since they I suspect are
copyrighted as well.
There is in the Library of Congress website a NIE section (Notice of Intent
to Enforce Copyright) that lists all the titles that have been registered
under the GATT treaty. There's thousands of titles. All foreign titles are
copyrighted immediately by this treaty of course, but this gives you an idea
of what has been registered and who owns the rights.
If the films were registered before January 1, 1999 they are under basic
copyright law. If any "GATT" film was registered after that date, the owners
of the film would have to directly send you a NIE letter to prohibit you from
using the title.
As for classroom, I don't know the specifics, but I can't imagine fair use
wouldn't cover that.
Milestone Film & Video