I may have gotten myself into a real corner here--can someone who has already played this game help me? In Day 1, when I first spotted Wilkes' moped, I wrote down the number in my notes, but didn't put it into Gabe's notebook. Now I'm in Day 2, the Sidney computer program is working, and it won't let me type the license plate number in.

Will I have another chance to input this number, or do I have to go back and replay the game from the point where it should have been copied into the notebook?

Hi.
you can manually type in the licensplate numbers.
When you se one of the bikes parked, you must look around and find out who it is and use your notebook in the game on the plate. Later you can scan the paper into Sidney.
Good luck.