The sample programs of the book have been tested with Open Object Rexx version 4.2.0.
The Open Object Rexx version 5.0.0 developers decided, with good reason, to replace the string SUBROUTINE in a system message with string REQUIRED. When loading routine libraries JP_Formtab.rex or JP_LWMod.rex, this leads to the (harmless) display of version messages which were originally intended only for the case of inadvertently calling them from the command line.
Fix: Download the full archive ballkk.zip (ZIP file, 3.0MB) again. It contains updated libraries that are compatible with 4.2.0 as well as 5.0.0.