It's now been more then a *year* since this was posted.
The problem is still there on each-and-every linux box I've ever used (10 of
them are mine, personally).
This problem was also present with Flash 6 on linux.

I was extremely excited when Flash 7 came out for linux, for this and *only*
this issue. How did they let such an obvious and frustrating bug go
uncorrected?

Besides audio-synch, the overall performance on linux is far below that in
windows. This is especially apparent on a dual-boot system, where the hardware
is obviously identical.

I have to assume two things:
*Nobody at Macromedia actually uses the linux plugin.
*Nobody at Macromedia actually cares.