FvwmEvent is spawned by fvwm, so no command line invocation will work. From within the .fvwm2rc file, FvwmEvent is spawned as follows:
Module FvwmEventor from within an fvwm pop-up menu:
DestroyMenu Module-Popup AddToMenu Module-Popup "Modules" Title + "Event" Module FvwmEvent + "Auto" Module FvwmAuto 200 + "Buttons" Module FvwmButtons + "Console" Module FvwmConsole + "Ident" Module FvwmIdent + "Banner" Module FvwmBanner + "Pager" Module FvwmPager 0 3