Saved game after getting to possums to play hide seek. Was playing in windowed mode.
Firstly, the game would refuse to start up after quitting but instead gave a nice access violation error. (Unfortunately I don't have the precise error message anymore).
An uninstall/reinstall fixed the issue.
Secondly, when I now load my possums game, I can't get anything to happen. The possums certainly aren't calling out hot/cold etc. I can move Fone Bone around - and read the book in places, but that's about it. Don't know whether I've missed something, or whether saving at that moment is a bad move.