WER400A ddname IS AN UNINITIALIZED SEQUENTIAL DISK DATA SET
EXPLANATION: The input data set was allocated but never opened for
output. Therefore, there is no valid data or end-of-file mark in the
data set. This condition usually occurs when a program abends and
the steps to create the data are bypassed.
ACTION: Write the appropriate data or end-of-file mark in the data
Check that the temporary files have been created correctly.