Wrong sounds playing

[movieman]

In the NASSP TLI code we load the TLI comms audio in orbitersound, then a few seconds later play it. Unfortunately we get the
launch countdown audio played instead.

I've stepped through the code, and it finds that the slot which was used to play the launch countdown audio is free (the code
doesn't want to use it again and it's not playing), and tells orbitersound to load the new sound in that slot instead.
RequestLoadVesselWave3() returns non-zero, so there's no immediate error, but unfortunately, when we go to play the sound a
few seconds later, it still plays the old sound file, not the new one!

It doesn't seem to be a timing issue, because I modified the code to load the sound much earlier but we still get the old
sounds rather than the new one.

Any ideas?
I