The problem I am having is the same thing, over and over: failure to advance. I can find no interaction with anyone in the game which advances the story.
While I am disappointed that nobody helped me out, I did manage to fix this. Eventually. Just in case someone else runs into this bug/problem, I am detailing the steps I took.
1. I went back to a previous save, one I knew was "good."
2. I assumed (correctly) that I needed to complete the Christmas Event to continue, and that is after "version .07."
3. I hunted around until I found the girl who was missing one CP (Rita, I think), and completed "version .07."
4. I then did the Christmas Event. This time, it played out as it should as all girls began with the correct status.
5. After the Event, I proceeded from "version .08" in the walkthrough, and eventually completed v.12.
The walkthrough leads you through the game, but only up through "version .07." At that point, you run into something of a "dead-end" with "90-End" (AKA "90 - Final"). Instead of leading you to the next step, you are left to figure things out for yourself. There is, however, a way to know what that next "step" is.
First, you need to keep track of which "version" (section of the full game) you have completed. Below 90-End, there is a link to "Versions" (at the beginning of the walkthrough) which indicates the path/person you begin with for each "version" of the game. Clicking on the "start" link of each version will take you to the beginning of a path, and it will soon become apparent whether you are in the correct place. If not, back up and try an earlier "version." You can also use the "Final Version Character Status" at the tail end of the walkthrough to determine how far you've progressed once you've gotten to "version .10." You do that by comparing the current status of the characters to that shown for the end of each "version."