ORA-01830: date format picture ends before converting entire input string

 I have created a function named date_to_run_emp_job so to use it in the interval section of the dbms_job, but I have the following error submitting the job with this funcion. The function compiled succesfully.

dbms_job.isubmit(100,'BACKUP_AND_TRUNCATE;','2/1/2010 5:40:00 AM','date_to_run_emp_job');

BEGIN dbms_job.isubmit(100,'BACKUP_AND_TRUNCATE;','2/1/2010 5:40:00 AM','date_to_run_emp_job'); END;
Error at line 1
ORA-01830: date format picture ends before converting entire input string
ORA-06512: at line 1

Script Terminated on line 1.

The job date_to_run_emp_job, is the following:

CREATE OR REPLACE /* Formatted on 1/27/2010 3:26:04 PM (QP5 v5.115.810.9015) */