The Cognitive Robotics Group at the University of Toronto provides a prolog file providing support for the Golog language for situation calculus (an extension of Prolog). http://www.cs.toronto.edu/cogrobo/main/systems/index.html. This has not yet been tested to determine whether it works with GPJ. Should you have difficulty finding this file then Daniel Thomas may be able to help.