I gladly accept your apology Dear Jerry, you have just restored my self-confidence! OK, now we can move on, especially coz I though we are going to do another set of troubleshooting spree 8like in to good-old-days) for Igor by throwing in question and ideas. I see nothing wrong even with bad ideas as long as they can be ruled out of the puzzle.
So, the reason I brought up the sample rate idea was because IIRC REW defaults to 48 kHz, while Igor didn't mention anything about his soundcard, but only admitted he has REW set to 44.1 kHz. To be honest, I wouldn't volunteer to predict what that s/rate difference would cause for creating FR graphs, just thought it would be a good idea to cross check it. If it's a bad idea, I'm ready to give it up.
Ah hah, now I understand. I agree with you completely that it is very important to make sure that the sampling rate on the soundcard and the REW configuration match. It is quite easy to have the soundcard at 44.1Khz, and REW at 48Khz, or vice-versa, which would result in false measurements. As long as both the soundcard and REW are set with the same values, it doesn't matter which of the two sampling rates one chooses.