Napolenic Wars-Audio problem

I have a strange audio problem when I join a game of Napoleonic Wars. I constantly hear dialogue and battle sounds and it seems like the sounds I should be hearing when I'm playing are not playing. The problem is not present outside of Napoleonic Wars. Below is a video link which I recorded to demonstrate the problem.
/watch?v=SmuQf6OAaiE  (copy and paste after youtube(dot)com as I am not yet allowed to post external links in this forum)
I have tried verifying the files on Steam but still have the same problem. Any help with the problem would be appreciated.

Install this:
http://download.taleworlds.com/mb_warband_setup_1153.exe

Then this:
http://download.taleworlds.com/mb_warband_napoleonic_wars_setup_1006.exe

Thanks, it works fine now.