I'm not sure about the employer part, but they called the people that had written me LOR's. I'm sure it's just to verify employment and such. Did you tell them it was ok to contact your current employer on your contact list?
I wouldn't worry to much about it. If they are calling, it's a definate good sign from what I've been told. I got the call today from the PD that I made it. They called my references about a week after I interviewed.
Hope this helps, granted I'm not really in the know. Just second hand information.
Good luck my friend and keep the faith.