audio device failed to initialyse ??

Hi guys!
maybe someone can help me.

i updated XBMC to the latest and right after,
i noticed that one of my movies, a 720P MKV file,
failed to play correctly.

upon launching the movie, i now hear no sound
and i see that "audio device failed to initialyse" error message...
but thing is, i didnt change a single thing except updating XBMC as usual...
that movie used to play just fine before updating!

other movies like those 700MB's avi files all play ok with sound and everything.

one thing i noticed, which is weird for me is that,
to get sound working in that MKV file im talking about,
i need to set the audio output to ANALOG instead of hdmi...
isn't that weird that i have to do that now when it used to work just fine before?

my HTPC is hooked to my 1080P HDTV via HDMI...

anyone knows whats going on?

how can i keep HDMI as audio output and have sound in my MKV movie
without seeing any error message poping up?

thanks!!!