Oh, geez, now I see what you're talking about. You're not on the "Ultimate Kombat Kode" screen, you're on the "Lost Treasures of Shao Kahn" screen, in which you choose your reward after beating the game. That's completely different.
The UKK screen comes up in place of the "game over" screen when you haven't unlocked all the characters. You don't even need to bother with beating the game to get to it, either. Just start a normal game on any difficulty ladder, lose a match, and let the "Kontinue" counter run out.
Right after that you'll be prompted with the "Enter An Ultimate Kombat Kode" screen with 3 bars that each contain 10 boxes (all of which are set to the dragon symbol by default). You then have 10 seconds to enter one of the UKKs. It's just like entering the versus screen codes, only it's expanded to include the high punch and high kick buttons on both controllers. From there, just use the information we gave you above.
Also, since you need to use the buttons of both players to enter the code, you'll probably want to configure the 2nd player's buttons to something you'll easily remember. I personally have the 2nd player controls mapped on the number pad of my keyboard to resemble the arcade controls (7=HP, 1=LP, 5=BL, 3=LK, 9=HK), which I did especially for putting in the UKKs.
Good luck!