so far we did not specify the naming of the file created by kwave.
kwave creates files where the namings are just based on the current time (hours:minutes:seconds).
for multprocessing scripts this can cause errors since different processes (which are creating the same file within one second) are refering to the same file path and thus overwriting it / deleting it.
one can overcome this problem by specifying the file names in a unique manner (using process ids)