There seem to be many glitches with the Tactics Trainer feature.
Sorry, should have stated this originally.
I believe there have been other threads in which people expressed that the tactical problems within tactics trainer have flawed solutions. It is not so much a computer problem, but a tactics problem :) I think there was a different thread in which Erik asked that all flawed tactics problems be posted, so they can be checked out.
I have seen ones that if you can move in two ways and mate but it only gives you credit for the one the computer has recorded.
I also notice that some of the tactics are not really tactics as much as half a game worth of moves.
I noticed their seems to be an error in the calculation of percentages. My statistics right now are:
Problems
My passed score is 17/20, or 85%, and my failed score is 3/20, or 15%, which add up to 100%. Right now it adds up to 110%.