REP-0004: Warning: Unable to open user preference file

When we submit concurrent request, we may see below error in log file .

ERROR:

Enter Password:

REP-0004: Warning: Unable to open user preference file.

Cause:

This message occurs when the concurrent process attempts to open the Oracle Reports executable and your local preference file cannot be found or opened. This is just a warning, so the request will continue to run even if this occurs.

Solution:

To resolve the warning, copy the prefs.ora file from your Reports Builder $ORACLE_HOME/tools/admin/ directory into the Applications $HOME directory.

Example:
Copy of the file prefs.ora in the directory /sharp01/prod/apps/tech_st/10.1.2/tools/admin to the directory  /home/appprod/.

NOTE:
For a report developed by xml publisher getting the same error, create/HDDATA/xml_tmp directory (environment dependent) on the system server after checking Administration from XML Publisher Administrator responsibility -> Configuration -> General -> Temporary directory column is /HDDATA/xml_tmp.