These .wav files won't produce any sound in LMMS. They work fine when I play them in the Media Player and other .wav files are completely fine, it's just this sample pack.
I PROGRAMMED MP3 SUPPORT INTO LMMS : r/lmms
Tutorial - How to import a sample in LMMS (1 minute tutorial) - YouTube
LMMS – Importing Sound File | Gjaiop
LMMS - Wikipedia
LMMS Free Music Production Software: Free Alternative to FruityLoops