I tried the suggested fix but it didn't make any difference. The problem is the menus at the top right <File - Edit - Control....> disappear when the plugin is installed. Creating the MPlugin directory and moving MPlugin.DLL to the new directory made no difference. The application top title bar is gone also.
Don't know what to do next.
I had this problem also - if the plugin is installed, my file menus all disappear.
However, after some trial and error, I found a right-click menu for evillyrics close to the 3 little "open/close" dots at the top left. Find the menu, select options, and the evillyrics option box opens.
Uncheck "skin titlebar". This fixes the titlebar problem, but prevents evillyrics from opening at iTunes launch.