Hi Arindam,
I am just wondering why you made the decision for making timestamps(update date and time) in the primary key.
I think removing the below fields as primary key will solve your issue.
Update Date - Update runtime system date (Not required as PK)
Update Time - Update runtime system time (at start of run) (Not required as PK)
Try making the update date and update time non key field and rerun the program.
Regards,
Karthik