SQL> show user
USER is "USR"


SQL> delete from SYS_FBA_DDL_COLMAP_26338;
delete from SYS_FBA_DDL_COLMAP_26338
            *
ERROR at line 1:
ORA-55622: DML, ALTER and CREATE UNIQUE INDEX operations are not allowed on
table "USR"."SYS_FBA_DDL_COLMAP_26338"


SQL> delete from SYS_FBA_HIST_26338;
delete from SYS_FBA_HIST_26338
            *
ERROR at line 1:
ORA-55622: DML, ALTER and CREATE UNIQUE INDEX operations are not allowed on
table "USR"."SYS_FBA_HIST_26338"


ORA-55622: DML, ALTER and CREATE UNIQUE INDEX operations are not allowed on table “string”.”string”

Reason for the Error:
	An attempt was made to write to or alter or create unique index on a Flashback Archive internal table.
Solution
	No action required. Only Oracle is allowed to perform such operations on Flashback Archive internal tables.