Thanks. I installed at-spi, so now the module 'libatk-bridge' is found. However, it now reads,
(gedit:3322): atk-bridge-WARNING **: AT_SPI_REGISTRY was not started at session startup.
(gedit:3322): atk-bridge-WARNING **: IOR not set.
(gedit:3322): atk-bridge-WARNING **: Could not locate registry
So, to hell with it. Gnome programs whine too much. Goodbye gedit, hello leafpad. Goodbye brasero, hello k3b. Goodbye sound-juicer, hello ripperx. Goodbye totem, hello smplayer. Goodbye rhythmbox, hello moc (mocp). Etc. Whining gnomes are no longer welcome on my computer.