Hi,
I received the same problem for my Microsoft Word version 14.4.6 (for home use). I called Microsoft Technical Support and they said that since it is past the 90-day warrantee period, they could only offer me a new product for $99. For those that have received their Microsoft products from their university or company for a huge discount or even free, I would suggest going straight to IT support to get a new version. For those that have surpassed the 90-day warrantee and do not want to pay $99 to fix the glitch, there's an option to input audio onto the file from the top drop down menu under "insert." You can use Garageband, Quicktime, or upload an audio file from your smartphone's recording app. Also, if you have your product key and product ID on hand, maybe you could try uninstalling and reinstalling the product.
MacBook Pro, Mac OS X Yosemite (10.10)