OPEN of Checkpoint File <dsname> failed
An OPEN of the Checkpoint File of the indicated dsname failed during initialization of Application Performance Analyzer. This probably indicates that the data set existed with incorrect characteristics. The Checkpoint File should be a physical sequential (PS) data set with unblocked, LRECL=1024 records.
Application Performance Analyzer terminates.
Attempt to resolve the problem based on the information available in the message and restart the job.