Just put it in Shredder to make sure. I had to reduce the number of pieces, so played Nxe7 and Kxa5, gives win in 31 moves for white. So I guess it isn't an easy win but still a win.

I admit at first it looked winning to me but then I thought, the composer and the website know it probably better then me (not thinking that they would have made an error). And guessed that with the White king that has to do alot of walking around it might be a draw.