Incest patch for 0.24 breaks when interacting with Elin. I am using the most current version, downloaded from the first post.
I'm aware this issue has already been responded to elsewhere in this thread, but the response of "use the most recent patch" doesn't resolve the problem.
EDIT: I've solved this problem for myself by decompiling the rpa files then manually editing the original script.rpy. I'm attaching the file here, you can just copy it into the "game" directory if you want to use it. It is, as of now, completely untested though, so you've only yourself to blame if it breaks somewhere. It's worked for me so far though.