I believe I have a similar issue where the pack is loaded but nothing plays.
No sounds in game or in preview. Achievements are shown and the event tracker is working. I believe everything is in the right place (see screenshot below). I can manually play the sounds files in PooNannersVPK\* through VLC player and other voice packs do work fine (I tested default and Tiny Tina). I'm on version 10.2.5.