What version of PlayOnLinux are you using? The current is 4.3.4 If World of Warcraft is a 32-bit game, then you don't have to use a 64-bit virtual drive (wineprefix) but I use it for every game these days. Also make sure you have installed Stable Wine from your package manager. PlayOnLinux will use that for the "default" wineprefix and basic setup of installing virtual drives. Can you go to Tools > Wine Manager Then download Wine 5.0 and Wine 5.0 64-bit?