PHost combat must be played by PVCR, PHost's battle viewer. The built-in battle viewers in planets.exe and Winplan can not display PHost combat; they will display complete garbage or crash.
Information on how to install PVCR for your client is described in the Combat section of First Time with PHost. This document describes how to use PVCR.
PVCR is a 16-bit DOS program. It can play combat generated by all public PHost versions that ever existed, so there's no need to keep older versions.
