I also had to figure out how to enter chess notation. As it turns out you have to add "x" after the piece if you want to capture or "+" suffix for check.
Ah. That might be it... Anyhow after staring at that chess challenge I was sure to get a mate in two moves with the Qh6 but the captcha filled with numbers plus the add to 25 left me with only 3 to spare... So no way am I winning this game.