My loss against rybka with the english

Hi guys. I was playing online at FICS against a guy who timed out at move 8. I saved the position, and started playing against rybka 2.2. Naturally I got my ass kicked pretty bad. But I'm wondering if you guys could help me flip through the game and find out where I went wrong. Towards the end of the game I was desperately trying to queen a pawn, but rybka thwarted my plans.

30.) Nd5+??

I am no expert here but I think Rybka gives its own analysis and ratings of positions - so that should be able to tell you where you went wrong - I do this sort of thing all the time with my games - I use Shredder - and it is a helpful way for me to learn and reflect after I play games.