Please note:

The Laserwriter, Adobe PS Driver, version 8.5 is recommended to be used with this PPD.
Installing the Adobe PS 8.5 driver overwrites a file called 'printinglib' in the 'extensions' folder.

After installing this Adobe PS 8.5 driver, the Laserwriter 8.5 and 8.6 may not work properly
anymore.  This problem can be avoided by making a backup of the 'printinglib'file, before
installing the Adobe PS 8.5 driver.

After installation, overwrite the 'new' printinglib with the backup and everything will work fine.