Some time around 1996 I was trying to get MCSD and they failed me by no more than 3 points 8 times on the last test. I had bought nearly every book on the subject. I have lost faith in these tests. There was even a question asking me if i'd suggest using Microsoft products or not to a client.
I think they just didn't want to give me the certification. I even asked to challenge it, and I was told I could only challenge a question.