The Yet Another Time Tracker Presence module depends on Yet Another Time Tracker module. This is not in the yatt_presence.info file but it needs to have
dependencies[] = yatt added. Otherwise if the presence module is enabled but not the main one, it will throw a fatal error to an undefined function when someone clicks their presence button. I am not aware how to change the files hosted here on drupal.org so I am posting a bug with a fix.