Support from MyVideoLib is surprisingly fast and informative.

I received this information regarding my playback problems:

Windows Media Player (at least 9th and 10th versions) mixes all audio streams together and doesn't allow to switch between them.

Download and install this free codec pack:http://www.free-codecs.com/download/K_Lite_Codec_Pack.htm

VideoLan http://www.videolan.org/ will be the best choice for playback as it also supports playlists: you can add movies which have 2 or more parts into a playlist and it will switch between parts automatically.

Other freeware/shareware usable players are
BSPlayer http://www.bsplayer.org/
Lightalloy http://www.softella.com/