How do I correctly input Date in Oracle SQL

Question

I created a table with parameters:

GUIDE_NUM   NOT NULL CHAR(4)  
LAST_NAME            CHAR(15) 
FIRST_NAME           CHAR(15) 
ADDRESS              CHAR(25) 
CITY                 CHAR(25) 
STATE                CHAR(2)  
POSTAL_CODE          CHAR(5)  
PHONE_NUM            CHAR(12) 
HIRE_DATE            DATE     

But when I try to insert values into the table for example:

INSERT INTO GUIDE VALUES('AM01' ,'Abrams', 'Miles', '54 Quest Ave.','Williamsburg','MA', '01096','617-555-6032','6-3-2012');

There seems to be a problem with the DATE syntax because Oracle keeps displaying:

ORA-01843: not a valid month 

and I even tried inputing different date formats like '06-03-2012' and it keeps displaying the same error.