some sounds not playing on Windows 8

[FORD JR, CURT]

We've got a project that involves many sounds, all accessed through players. On most cards the controller is visible; on two cards with shorter sounds, we have small buttons that set the filename of an invisible player and start it playing.
It's been working well on Mac, XP, and Windows 7.

We've just had a report from a user on Windows 8 that sounds are working properly only on the cards with buttons and the invisible player. On cards with controller bars, the "sound doesn't work" (haven't been able to get more detail as to what exactly does/doesn't happen).

I haven't been able to get confirmation that the customer has QuickTime installed, though I would have assumed that if it's not, no sounds would play at all.

Anyone have any ideas why the controller might not work on Windows 8, though sounds played by an invisible controller do work?

-Curt