This is a PPWIZARD command line switch.
This switch only has affect when generating rexx code under OS/2.
PPWIZARD always checks the generated code by asking the interpreter you are using to validate it. The OS/2 classic (not sure about OO) rexx interpreter does not do as good a job as regina in detecting syntax errors.
By default ppwizard will use the OS/2 version of regina to perform a second syntax check assuming that the first (done by OS/2's rexx) passed it. PPWIZARD will look for a file called "ROS2REXX.EXE" in the same directory as PPWIZARD as well as in the PATH.
This switch allows you to either turn off the checking altogether (pass '-') or specify the full name of the rexx interpreter.