FPX1005E Unable to open file `DDname`

Explanation
 The exit was unable to open the specified file.
One of the following  might  be in error:

The XDRDATAx DD statement has been omitted
from the JCL

The suffix associated with a function passed by the user-written
program does not match the prefix on the XDRDATAx DD
statement contained in the JCL.

System action
 Processing ends with an abend code of 3599.

User response
 Correct the problem and resubmit the job.

FPX1005E Unable to open file DDname