Really you should try once more to go over all the steps. It's often the simplest of things that cause the problem when portforwarding. Of course that's also the reason why they are so hard to spot.

Like the other day, I spent over two hours trying to figure out why all of a sudden I couldn't connect to my router through wireless. Turned out a new IP changing software I used I accidentally put 3 instead of 103 as the final number of my IP. Since the only IPs allowed to make changes to it were 101-104, 3 of course was blocked.