https://bugs.winehq.org/show_bug.cgi?id=32809
--- Comment #5 from Rodrigo Davy rodrigodavy@gmail.com --- (In reply to winetest from comment #4)
Wine source code still claims a stub. So you are most likely using same prefix where you have winetricks -q wmp9 already preinstalled. This doesn't sound correct to me.
I deleted the .wine prefix and regenerated it just to be sure, that KwSing program doesn't complain about wmvcore