My friend had this happen last year. She was on hold for 10 weeks (at VCU/MCV), then got interviewed, waitlisted and finally accepted.
It just means you haven't been rejected, but you aren't on the top of their list so they will interview you later in the process. My firend did have to contact them after 10 weeks to ask if they were going to interview her. They happen to have a cancelation that week so they put her in that spot.
So it really isn't unusal to be put on hold for an interview. Hey, it's not a rejection.