Just because a defendant isn't convicted, it doesn't mean the complainant lied.
This was my first thought. Finding someone 'not guilty' of a crime, and I mean any crime, doesn't mean they didn't do it. Just look at O.J. Simpson.
I think some people confuse the fact that over 90% of rape trial see the defendant cleared, and take this to mean that a large number of those cases are where the woman lied, but it doesn't mean that at all. It simply means that in the jury's mind, there wasn't enough evidence to convict.
There are men walking around around who were cleared in a court of law, but who did commit the rape, and are therefore rapists. My brother-in-law is one of them.
There are a small number of women who do make up rape claims, but more often then not they admit the truth sooner rather than later, and thus such cases rarely get to the trial stage.
So small is the percentage of women who are believed to make up rape claims, that my first inclination would always be to believe the woman, as the vast majority of women are telling the truth.