fabledgoat:
When I follow this link you supplied it works, but if I follow the link from the IFX Homepage then click on it I get the 404. This is the link I see on the homepage
http://www.imaginefx.com/02287754331657294825/the-science-of-painting-space.html
[Edit: I would add that, that link appears to go to a different tutorial by the same person, at least the screen shots are different than what I'm seeing]