I’ve had all sorts of issues installing the Fiery E10 driver (installed in a KM Copier) to work under 10.6 – after installing it, the Printer preference pane would have a yellow warning triangle and when you opened the printer window, it’d say something along the lines of the printer is not properly installed.
It turns out that it’s a simple matter of fixing the permissions.
Download the driver, either from the web page published by your printer, or from Konica Minolta Europe.
Install it as normal (Oh KM, why do you insist on using a non-standard non-OS X .pkg installer?)
Once it’s installed, type the following two lines into the Terminal, entering your admin password when prompted:
sudo chown -R root:wheel /usr/libexec/cups/filter
sudo chown -R root:admin /Library/Printers/efi
Now, add the printer as normal. If you have already installed the driver and added the printer, there’s no need to remove it and add it again, this will get it working.