Hi mate,
If you fail the test, you can't drop it. Did you complete your high school in Australia (Or A levels overseas etc)? Did you get above 60 in English? Can you write a paragraph about random issues? If yes, you passed. The test is only set up to identify and HELP students who can't coherently write or express themselves. Mainly international students, so BUSS1900 - a 0 credit, free course, is actually a great help for them. Even though almost everyone passed, a couple of friends and I still went to some of the lessons (had a great tutor).
And no, you don't need to do anything.