IDSTIOST02 - DD card for "ddname" is missing

Reason:

(Non-VSE only) One of two possibilities for error exist:

The command SET SOURCE DDNAME ddname specified a file-name that was present on the IDSYSFT assembly but was not present in your JCL. Specify ddname in your JCL or change the SET statement to correspond with your JCL.
The JCL was misspecified without a DD statement for EXTSRC.

Action:

Correct the errors and re-specify.