Changing the QuickTime Sound Out didn't make any difference.
In my e-mail to Alida support I mentioned where the problem was -
when I'm in the Conservatory and turn the knob or triangle device to move the white marble on the 'guitar' model.
I then wrote that I was able to advance beyond this point by using a different PC and copying the saved games back to my original PC and, as of now, I'm still able to play the game.
They wrote back:
I'm investigating this one as I've had other reports. It seems it may be occurring only in that one area so I hope you can continue to enjoy Alida.
"Don't cry because it's over, smile because it happened."