oracle高手请进，下面pl/sql 块错在那里？？

declare
type newStruct is record(
c1 number,
c2 number
);
type NTab is table of newStruct;
type Cursortype is ref cursor;
nList NTab:=NTab();
myCursor Cursortype;

begin

nList.extend;
nList(1).c1:=1;
nList(1).c2:=2;
nList.extend;
nList(2).c1:=11;
nList(2).c2:=22;
dbms_output.put_line(nList(1).c1);
dbms_output.put_line(nList(1).c2);
dbms_output.put_line(nList(2).c1);
dbms_output.put_line(nList(2).c2);

--此句出错
open myCursor for SELECT t.* FROM TABLE(nList) t ;
--open myCursor for SELECT * FROM TABLE(CAST(nList AS NTab)) t ;
end;


-----------------------------------------
执行后出错信息：
declare
*
ERROR 位于第 1 行:
ORA-00600: internal error code, arguments: [15419], [severe error during PL/SQL
execution], [], [], [], [], [], []
ORA-06544: PL/SQL: internal error, arguments: [pfrrun.c:pfrbnd1()], [], [], [],
[], [], [], []
ORA-06553: PLS-801: internal error [0]