You don't have to have i-134. It is just one of the evidence you want to present to VO for your parents to indicate that you have enough financial support for their stay. It is helpful but not required. BTW, it has nothing to do with school. You download it from USCIS (former INS) website, fill it out, and go to either bank or student service to have it notarized (usually it is free service). Good luck,