Please see the following docs.
Viewing Log or Output Files in Applications Fails With: VIEWER-READ ERROR, FDPSTP failed due to ORA-20100 (Doc ID 370544.1)
Concurrent Processing - Troubleshooting Concurrent Request ORA-20100 errors in the request logs (Doc ID 261693.1)
Difference between APPLPTMP and APPLTMP Directories in EBS (Doc ID 1355735.1)
On A Multi-node / RAC Installation Is $APPLCSF And $APPLPTMP An NFS Mount Point (Doc ID 371896.1)