I just called the USCIS Customer Service (800) 375-5283 and asked about this "NIW-PHYSICIAN" problem. They asked me whether or not I mentioned "physician" anywhere in my petition, and I told them no. Then I was told to send a fax to TSC, with copies of my approval notice and Form I-140, and explain in the cover letter that there is nothing about "physician" in my application and ask them to fix the problem.
They give me the fax# for TSC, which is (214)962-2632. I will go ahead do that.
For anyone who doesn't have a clue what I'm talking about, here is the related post:
http://web.wenxuecity.com/BBSView.php?SubID=immigration&MsgID=131355