(which I have to do manually by putting the files in C/Windows/Resources/Themes because the built-in thing in WSB always gives an error)...
Odds are, the style isn't being applied via the Personalization panel, either. Perhaps you wouldn't have noticed because the style is identical to the default in every other way or something. Make sure you have UxStyle or a UxTheme Patch or whatever you prefer installed and working. If you're using UxStyle, try going to Services.msc and restarting the "Unsigned Themes" service.