Plugin issue

Hello! I've been trying to run a plugin on the program (the "More sounds options" plugin that's in the "Plugins" page) but it's not working. At first, I thought that it was because of a problem with the howler, but then I tried to run other plugins and they didn't work either. I could swear I put them in the correct folder (the "plugins" folder), so I don't know what am I doing wrong exactly. I must also clarify that, around a year ago, I downloaded another plugin and it worked. Recently, I updated the program to the latest version, so perhaps that might be what's causing me problems?