just for you, I knocked out an audio cd from .flac source files.
During the burn, MC continued playing my current playlist, and I continued poking around on the internet...
The burn completed successfully, and the disc is currently playing away nicely on the Hi-Fi.
Using in_flac v2.1.3, I was set to write cd text, decode directly to disc at maximum speed, without any dsp or crossfade settings.
My system is not what you'd call high-end anymore...
AMD Athlon XP 2800+
1 Gb crucial RAM
TDK 16x ± DVD (re)writer
uptime around the 5 day mark and 64 other processes also running.
1st port of call is to check you're running the current version of the .flac decoder plugin...
Good luck,
-marko.