This may occur under two circumstances:
1) ColorSync is not installed.
2) ColorSync 2.5 or later is installed.
In either case, you need to follow these steps:
1) Install ColorSync 2.1.x, which was included with your Color StyleWriter 2500.
2) Install the Apple Color PhotoGrade Kit.
3) If previously using a later version of ColorSync, reinstall the newer version.
NOTE: Mac OS 8.5 ships with ColorSync 2.5.1. If you are installing the Color PhotoGrade Kit after installing Mac OS 8.5, you need to follow these steps.