What causes an unexpected exception error in the Receiver?

Here is an example:

842-ERROR-[Receiver_#1-T2]-[Receiver.java:177]-oracle.documaker.receiver.Receiver.logErrorMessage:
File Receiver error - unexpected exception:
java.lang.NullPointerException
at
java.lang.String.<init>(String.java:515)
at
oracle.documaker.dao.tables.jobs.JOBS.getJobObject(JOBS.java:805)
at oracle.documaker.dao.tables.jobs.JobDAO.putObject(JobDAO.java:229)
at
oracle.documaker.receiver.monitors.FileReceiver.run(FileReceiver.java:256)

This usually occurs when the Receiver cannot process the content of the input or extract file. To correct, check the validity of the input file. This file is located in the following directory:

temp\Receiver\errors

Any time the Receiver encounters an error when processing a file it will place it in this directory.