The DSC Mounter.pkg will be on the CD that came with your camera.
If you don't have the CD, go to the manufacturers web site and see if they provide a download for it.
Hi bobw! Thanks for your answer.
Unfortunately, I don't have that CDROM anymore and recently I re-installed Mac OS...
In the manufacture's web page (http://www.medion.de/) there's just the Windows' driver available for download! And in Apple's web site I can't find it either!