“ORA-06533: Subscript beyond count” from DBMS_STATS

SQL> EXEC DBMS_STATS.gather_table_stats('USERNAME','TABLENAME');
BEGIN DBMS_STATS.gather_table_stats('USERNAME','TABLENAME'); END;

*
ERROR at line 1:
ORA-06533: Subscript beyond count
ORA-06512: at "SYS.DBMS_STATS", line 34634
ORA-06512: at line 1

SQL> exec dbms_stats.gather_table_stats( ownname=>'USERNAME',tabname=>'EVENT',estimate_percent=>100);

PL/SQL procedure successfully completed.