Done a bit of research for you into this, and it seems its not addon related, but a wow problem.
I found this,
http://us.battle.net/wow/en/forum/topic/1208032112 which the user is having the same problem as you, even tho its from nearly 2 years ago, the solution is as follows:
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I wonder if you have older files somewhere it's trying to load and is failing. Let's try this: go to your World of Warcraft folder and open the Data folder. I want you to delete anything that might say oldworld in its filename. They're no longer needed. Delete the Cache folder that's inside the Data folder as that has all of your old cached/uncompressed sound files.
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[Taken from post 15 in the thread linked above]