XBMC uses the default libFLAC.dll from the win32 developer archive from flac.sourceforge.net The current version is 1.2.1, and the sources may be downloaded here: http://downloads.sourceforge.net/flac/flac-1.2.1.tar.gz The current binary dll is found in the archive available here: http://downloads.sourceforge.net/flac/flac-1.2.1-devel-win.zip