I remember looking at that game in the store. I think it said on there it has a "Friendly Mode" where it adjusts its difficulty to your play. If you were playing like that then it probably wasn't playing full strength. I don't think it's full strength probably wouldn't miss easy mates.
ELO of Fritz 9
Sort:
Oct 20, 2008
0
#3
Nowadays even 'bad' engines won't miss mates in 6 or less...probably not on full strength.
IT WAS TOO OBVIOUS. even the worst player in the world would have seen it.
Rook f6 was the move it did! It found the mate later, but how PATHETIC IS THAT?!?!?!
Look at it. R d8#
Fritz 9 didnt see it.
PATHETIC!
maybe it needs to join the endgame lovers group 
I got a cheap version of Fritz 9, but It missed mate a few times. Im asking myself how credible it is.