Forgive me if this is posted elsewhere, but I didn't see it.
My Ubuntu 6 / Cxoffice 5 iTunes install "worked", but had glitches everytime I "did anything else" while it was playing (e.g. open a terminal, refresh a web page).
I'll claim that the FIRST THING ANY COMPUTER MUSICIAN would do given such symptoms is look at buffer size.
I went to 100ms and 20 fifo buffers and everything is going swimmingly.
Configure -> Manage Bottles -> Win2000 -> Control Panel -> Click on the little "Q" icon...
Seems to me that a more liberal buffer should be the default. 100 ms of latency is fine for simply playing back audio (who cares if it takes an extra 70ms to start?)