If/when you interview, your interviewer may take note of it and bring it up. If they do, just explain the discrepancy. If not, they didn't feel that it was of any significance.
There isn't really a pre-req GPA that they look for, so maybe I am misunderstanding. Are you missing a course that is a pre-req or something? If that is the case, I would take that course. Otherwise, it doesn't matter.
Yah, I believe they are talking about credit hours NOT gpa. You need to give them a call or email. It may be a non-issue, just a mistake in communication/data-entry on their side.