Syntax to insert date column is incorrect, '20100913' in not in the 'YYYY-MM-DD' format but in the 'YYYYMMDD' format, like...

Code:
SQL> create table TBL1 (EMPNAME VARCHAR2(6)
  2  ,EMPID VARCHAR2(10)
  3  ,MPBDATE DATE);

Table created.

SQL> insert into TBL1 columns(EMPNAME,EMPID,MPBDATE)
  2  values('Joe',2,to_date('20100913','yyyymmdd'));

1 row created.