Shashank,
Thanks for the reply.
I checked the config file, I could see Delete _flag which is mapped to cnt status column.
I dont see the "=required" for delete_flag.
For your second question : csv file does capture the delete_flag or corresponding column.
However interesting observation is : if I just modify the same csv file with a different "EmployeeID" it works and updates the corresponding record.
Only for few records it throws this error, I guess there may be some backend business logic which checks and throws this error.
Its really difficult to find the root cause and there is NO technical reference by CA for this error.