IRXJCL is an utility used to execute REXX procedures in a batch JCL or in an Endevor processor. An example of such a REXX would be the Endevor table tool utility ENBPIU00.
The utility might end returning with RC 3637 as the processor step RC
This RC means that the utility couldn't find the procedure it has to execute, which is specified in the JCL PARM. Therefore the items to check are: