Why wont the internet class website let me log on!?!?!?!?

So im in Summer School, but its the internet course for Civics\Econ.. We only go once a week to take tests and stuff, since all the work is done online. The teacher gave us a website, and we are supposed to use our School ID # as a username\password. But everytime I try to log onto Aplusanywhere.com/vcis it says im not registered, but I know i am! What is the problem!?!?!?