Audio Sample rate issue

[Yuhaney]

I'd say your HDD is not fast enough for both FRAPS and audio recording at the same time, since FRAPS records with its own lossless codec. I would recommend entirely scrapping FRAPS and trying another software which compresses on-the-fly. I personally loved FRAPS and praised it for many years, but now I have changed my mind.

If you have NVIDIA GPU, I would recommend ShadowPlay (free).
If any other GPU: Afterburner (free), and use x264 codec to compress the recorded video on-the-fly.