Last year when I was accepted into the Animal Biology MS late after being rejected post-interview for the DVM, the registrar's office had a heck of a time with me too. For whatever reason, they initially had classified me as an entering DVM student rather than an entering MS student, so I was added to the class mailing lists and my Sisweb information had me down as a DVM student. I couldn't register for my research hours! What a tease, eh?
(obviously I got it straightened out, though my student ID card still says Vet Med Student instead of Graduate Student, even though I got it way after the issue was resolved!)