error in tactics program

At first, I thought I would think that I was right and would come to realize that I had made the wrong move.  But in two recent tactics problems, I know the program was wrong.  In one instance, I forked a rook and king with a knight and had a clear win of the rook.  But the tactics program called me incorrect and had me bring in another piece to win that rook.  But after winning the rook, I lost that piece.

Has this happened to anyone else?  Unfortunately, I cannot bring the puzzle back as evidence.

I can't tell by your recent tactics, none of the ones on you list look like they are right.

That said, it is very likely you just missed something in the line.

I can go back 14 tactics on the recents, but is it [possible to go further back?  The problem happened earlier. 

On the website ther are 25 on the full stats page. Didn't recognize it from your explanation so it may have been before that.

Harry, I'm at 1600+ on the Tactics Trainer and there are problems I get wrong where my first instinct is to think there's an error in the problem.  I've always found I was wrong.  Often you can look at the comments and someone will have pointed out why the "right" solution is better than yours.