Don't follow the guide with Samantha. At the point at the hospital where the guy who tried to have his way with her wanted to talk to you. DO NOT go talk to him. I managed to max corruption points with Samantha after 8 Chapters.
I don't know, but so far the only thing you get from her up to chapter 9 is just a bj other than that is touchy feely and kisses with max corruption points. Try to start over and forget about trying to befriend Emily. Like if there's an option to do something with Samantha at the beginning always go for that option. The guide on the net doesn't sometimes gives you specifics to go which character path. I start over a few times trying Emily's path and I still have trouble maxing her friends/corruption points. So far I have no trouble maxing corruption with the other girls in the house.