You can visit the pool but there's no second date with Samantha. Check the replay menu to see what's new. Also make sure you aren't trying to overwrite the old game folder with the new one.
After you can punish the girls yourself there is a cut scene on the Monday morning and it says chapter 2 in big letters. If you're in chapter 2 and you can't unlock the pool then all I can say is you've made a mistake downloading it or updating it. Just download the latest version. Unpack it into a new folder and play. Saves will transfer automatically.