Lacie Mini Drive Doesn't Mount to My Powerbook G4 Running On Mac Os 10.3.7


I've just purchased a Mac Powerbook G4.
I would like to be able to use my LaCie mini drive 20GB, but it doesn't mount. I've done the installation from the CD that came with the drive, and when I go to plug in the USB cord of my mini drive -- it doesn't show up on the desktop!
Not sure if the installer is an older version; I couldn't find (and not sure what it is I'm exactly looking for) upgrades on LaCie website.

Please help.