A lot of invisible files are on Mac OS X. Sometimes, i.e. to change serverfiles or prefs, it is useful to make them visible.
Just double-click the InVisibles icon, click "Visible" to make all of the invisible files become visible files. If you have carried out whatever processes you need to, double-click the InVisible icon again and this time click "Invisible" to make them all invisible again.
Free serialnumber - now even without e-mail (was mailware before). The serialnumber is now on the developers website: http://blog.tice.de/index.php?rubrik=software&content=invisibles_engl