Query re the legality of a move.

See game
http://www.littlegolem.net/jsp/game/game.jsp?gid=1495833
I am red and have thrown a 4.
It is possible for me to move my player on the third row to the empty square on the 2nd row on the left. This blocks both the ball and the yellow player.
My questions are:-
1. Is it legal?
2. Is it considered "bad sportsmanship".
Many thanks

Have posted it on the SS forum.

I always tought the point of these games were to not have such a thing as 'bad sportsmanship'.