A weird situation that's left me confused

About two weeks ago, the professor at my college that does the recruiting for the actuarial and mathematical degree tracts informed me that a very prominent insurance company was looking for interns and potentially full-time employees and all I had to do with email my resume to someone. What made this situation even better was that I had met this someone several times at career fairs and had talked to her for a few hours about the company, her position, the job, and all that jazz. I wasn't too surprised when I got an email back that I'd be getting a preliminary phone interview in a day or so, though I was surprised since I'm what I would consider to be the most average actuarial student.

I schedule this phone thing, get the call that's supposed to be just a half-an-hour, but end up laughing, joking, and shooting the shit with the guy for over an hour. The guy hangs up after telling me that even though he has no control over in-person interviews, he's going to really recommend that I get to come in and meet with everyone. If I said that I was ecstatic, it'd be an understatement.

So, I get an email the next day, asking me for my availability over the course of the next week. I tell them that I absolutely cannot make it one of the 10 business days because I'm sitting for FM (2nd try) and after another day goes by, I'm emailed directions to one of the main offices, a collection of names of everyone I'll be meeting with and when, a list of several nearby hotels and motels to crash at if I don't feel like making a 3 hour drive home after the day is done, and everything seems peachy. An hour later, though, I get an email back that tells me that the interview will unfortunately have to be rescheduled, but no explanation or reasoning for it, even when I responded asking what had went wrong.

It's been 3 days, and neither the HR lady, my contact that I know, or phone interview guy have responded to any emails. A classmate of mine, whose name I recognized on the initial email about phone interview times, got the same treatment. We're both pretty much confused as to what has happened and why we suddenly got the silent treatment when we both were on our way to get an in-person interview.

Should I be worried? Is this typical and just occasionally happens?