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

Symptoms:

All concurrent requests that run REPORTS are printing the following warning in the request log.

“REP-0004: Warning: Unable to open user preference file”
Your local (customized) Oracle Reports preference file could not be opened.
This is just a warning, so the product will continue to run even if this occurs.

The possible causes of this error include the following:

CAUSE 1: The file was not found under the specified name in the specified location
CAUSE 2: You lacked the necessary privileges to open the file.

SOLUTION [ID 1120529.1] :

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 /u01/prod/apps/tech_st/10.1.2/tools/admin to the directory  /home/applprod/

This should solve the Problem !!!