Cause
ADDM analysis was attempted on imported Automatic Workload Repository (AWR) snapshots with incompatible character set.
ADDM analysis was attempted on imported Automatic Workload Repository (AWR) snapshots with incompatible character set.
Perform ADDM analysis using a database with the same version and character set as the original database.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e12700.htm
Browse all solutions to database errors from Oracle, MS SQL, or MySQL