Different return for Oracle 9i and above when using proc to insert more than one column of Varcahr2(

I created a table with 3 VARCHAR2(4000) fileds in Oracle 9i.

create table tbl_varchar(a varchar2(4000), b varchar2(4000), c varchar2(4000));

Then, I used proc code to insert values("abc" is a, "def" is b, "ghi" is c) into this table. It returns error "ORA-01461: can bind a LONG value only for insert into a LONG column". But when I inserted only one value(such as only a field "abc") into the table, It works well.

I just created the same table in Oracle 10g or 11g.

create table tbl_varchar(a varchar2(4000), b varchar2(4000), c varchar2(4000));

I also used proc code to insert 3 fields into the table. It works well.