I had a similar problem, I'll tell you how I solved it. Understand that I am a newbie at video editing and Premiere Pro. I shot videos on a DSLR (.mov) and then transferred them to my computer. I then imported them into Premiere CS6. The videos played fine, and the sound bars indicated that audio was playing, but there was no sound. The clips I imported played fine in Windows Media Player. I did everything suggested on the forums, but to no avail. Then I thought of something no one else had suggested, and it worked!
I ordered my Rain Stratus computer already set up with Premiere CS6 installed. When I opened a new project, it by default chose Black Magic Design presets, since that is the video card I have. Being a newbie, I just went with that. But since the video I was importing was not captured by my Black Magic video card, it was the wrong choice. It took awhile to figure out, but I finally realized I needed to choose Digital SLR as the sequence preset when I created a new project. Then the audio worked!
One more thing I had to do, though, before it worked: in PremierePro, go to Edit/Preferences/Audio Hardware. I had to change the hardware from Black Magic Audio to Premiere Pro WDM Sound, click ASIO settings, choose my speakers, and then check the box marked "device 32-bit playback" (even thought I have a 64-bit computer.)
I hope that helps someone else from going through the same frustration.