if you're in OPT now and have received a receipt # for H1-b, but you are enrolling in kaplan for the sake of status, you are fine. In this case, H1-b won't be affected. Since you're in OPT, ie F-1 visa, you wont have any change of status if you enroll in another program. However, if you applied for any different visa type, H1-b would be affected. I'm in the same state, and i confirmed this with my int'l student advisor. Talk to your int'l student advisor at your school for confirmation.