After 5 minutes of waiting this post a reply page isn't probably loaded, oh and official page loading time is please wait
But now back to topic:
If the CPU of your computer has to work very hard than it will first compute the AI stuff and if the CPU is free again the music will start again. That is the case usually when the human turn starts again. Therefore if the music track ends during the AI turns than it will start again the human turn begins again.
Usually I have not the music on, either. I am listening music from my CD-player, and sometimes I put the CTP1 CD into it. You could do it with the CTP2 CD too. Of course afterwards you started the game. You have only to copy the wonder videos into the correct directory. That should be:
..\ctp2_data\default\videos
-Martin