No sound in the Roman campaign

[UnLimitedSD]

I played a Roman campaign for a while and all of the sudden, while I was in the game, the sound disappeared. I thought restarting the game would help, but I was wrong. I don't have this problem when I try playing other campaigns, it's only with the Roman one. I tried doing this, but I didn't have anything named "musicb". I Googled a bit, but I couldn't find anything useful.
I have Windows 7, I should have the newest version of Rome (I'm playing it on Steam).
Can you please help me? Thanks

[Brusilov]

What is the full error message? You've only mentioned that "I didn't have anything named musicb".....