I've had problems trying to log on there from day one, it's a bit hit and miss, sometimes I get on and sometimes I don't.
I have suggested more than once a download section here on the forum, and not just for the tutors practice material but also for important stuff like PDF's of airbrush manuals and blow ups exploded diagrams of specific airbrushes and that sort of thing, basically anything at all that's helps people to understand more about there equipment, and I'm pretty sure
@Don Wheeler would have a lot to contribute if we had such a section.