Oracle Error Message
ORA-28507: error in data dictionary view string
Reason for the Error
The initialization parameter table for the Heterogeneous Services was not available, or its structure (number of columns or column types) was incorrect.
Solution
Verify correct installation of the following Heterogeneous Services’ initialization parameter views: HS_CLASS_INIT and HS_INST_INIT. If these views are not available, make sure you ran the script CATHS.SQL in the $ORACLE_HOME/rdbms/admin directory.