OK, I have run into a strange problem (I think)...
After the onsen (Japanese bath) with Mao and Nao, I go home, Mao is calling me on the computer, but I am not receiving her dialog. Only mine. No voice, no text, so it is one sided (just me) and I don't know what I am answering/responding to.
I was able to go to their apartment, Mao greets me at the door.. I go through a couple more scenes, but there still is no Mao dialog (haven't seen Nao yet).
UPDATE:
Ok, found the problem. The Shawn's Mod (latest version) is causing that. If I remove that (the MOD folder), it works fine.