I have converted the Sound alarM2 file posted by RTLSVU to LabVIEW 15. This should fix the error that you where experiencing.
It does not fix the fact that this code is completely wrong. The "use system alert" boolean input to beep.vi is NOT a selection between "sound" or "no sound" (even though it looks that way because it is slightly broken in recent 64bit Windows :(). It is NOT advisable to leverage a bug for central functionality because things could change in the future!
Similarly, it is wrong to place the sound inside the producer loop. The OP required a two loop solution with all processing in the secondary loop.
I already solved the sound problem, it just needs a few minor adjustments if a different logic is required. Right? Why not start with that code?