The step which failed due to insufficient region was coded as:
//STEP445 EXEC PGM=PTLDRIVM,
Recommendation would be to specify REGION=0M on step or JOBCARD if allowed.
REGION=0M is recommended and the REGION specification on the JOBCARD
will override the step REGION specification. If REGION=0M is not allowed,
then specify a REGION larger than 16M or lower than the available
initiator REGION available such as REGION=8M.