1. hit large SUBMIT NEW SCORE button
2. enter your score over the 0 in the score textbox
3. hover away from it and select either the player dropdown or the game dropdown
4. after an animation icon that "validates" your score is completed...
5. the I AGREE - SUBMIT SCORE button is enabled and ready to click
that is it. double check if your score was entered on the list, if not, maybe your entry was after the deadline?