The description for RNX1251 says that "If the major return code is 80 then
a system or file error occurred and programmer action is required to fix
the problem." It gives no indication of what minor return code C0 means.
Is it possible that splitting the EXFMT into WRITE and READ operations
might help? (A question for Barbara?) If for no other reason, I'd encase
each of them in a MONITOR block. Maybe retry 3 times to see if it resolves