No, i didn't. I was even using it few times with original modloader (not liberation). Also i read in the liberation modloader description that some mods may not work.
If u say u dont even see FPS counter anywhere i assume that the liberation modloader don't even load _missions.gsc. I have no idea why is that happening, maybe its not loading that files at all, maybe file is too big. I have no clue whats the problem at all.