 An attempt to change the first specified LOG_ARCHIVE_DEST_n parameter (n = 1, 2, ... 10) produced a destination that duplicates the session destination value of the second specified LOG_ARCHIVE_DEST_n parameter. This error can occur when setting a non-NULL value with the ALTER SYSTEM statement. Or, this error can occur when setting a NULL value with ALTER SESSION command, because then the associated system destination value may appear as a duplicate.