Google Earth application not playing SoundCues on Linux or Mac

[GoogleCodeExporter]

I've created a Google Earth network link here:
http://mapofmemories.generamics.co.uk/tour/download
which links to a tour file here:
http://mapofmemories.generamics.co.uk/tour/kml

There are gx:SoundCue calls in the gx:Playlist throughout the tour - the
first mp3s should cue at around 30 seconds into the tour.

Tested the files on Google Earth application on the following OSs:

Linux:
GE: newest x86 32bit version (installed from http://earth.google.co.uk/,
not from repos, on vanilla OS)
OS: Ubuntu 9.10 Karmic

Mac:
GE: fresh install from http://earth.google.co.uk/ (testing on 2 separate
Macs, one was a vanilla OS install)
OS: 10.6

Windows:
GE: fresh install from http://earth.google.co.uk/
OS: Windows XP running in VirtualBox

Windows XP plays tour perfectly, SoundCues trigger at correct points during
the tour.

Neither Mac nor Linux play any of the SoundCues.

I would have imagined that this bug would have been more widely reported,
but I can't seem to find anyone else with the same problem.

Original issue reported on code.google.com by generam...@gmail.com on 26 Jan 2010 at 11:59