On some Macintosh System 7.5 and 7.6 machines, you may get a warning when GPSy starts up that "AppearanceLib" is missing. AppearanceLib is a shared library that provides a 3-dimensional look to applications and is part of the new Appearance API that Apple is promoting. AppearanceLib is built-into MacOS 8.x machines, so there should be no reason to install it on those platforms.
You will need to download and install AppearanceLib if you don't already have it. You can download a copy of the AppearanceLib SDK with AppearanceLib 1.03 extension at:
Install the system extension and control panel from the kit and restart your machine. Note that you'll get additional benefits from installing this extension -- a number of your applications should now display using the new 3D appearance and you can select different "themes" from the Appearance control panel.