HKEY_CLASSES_ROOT\.FlashFXP_PI for parent dir icon
HKEY_CLASSES_ROOT\.fqf association for FlashFXP queue files.
HKEY_CLASSES_ROOT\FlashFXP.Document
HKEY_CLASSES_ROOT\FlashFXP_PI another entry for parent dir icon
just search for "flashfxp" and whatever you'll find chances are belong to flashfxp
i'm pretty sure uninstaller removes all of this.