Sound inaudible; only sort of stutters

[Arnoud]

I wanted to start a new movie project. Open Shot does import the .MOV files I shot with my camera, but upon watching/listening to my raw footage, the accompaning sound is inaudible. The sound only results in a sort of stammering instead of a smooth playback of image and sound. The sound is recorded correctly though, since I am able to listening to it in a normal way in another movie editor whilst watching the raw footage. I cannot edit ofcourse when I am not able to first hear what the original soundtrack sounds like!
My system is of 64 bit nature; runs on Debian (Jessie, the latest version)