MySQL Replication Error

I am getting an Error on Slave as:

could not execute Write_rows event on table mydatabasename.atable; Duplicate entry '174465' for key 'PRIMARY', Error_code: 1062; handler error HA_ERR_FOUND_DUPP_KEY; the event's master log mysql-bin.000004, end_log_pos 60121977

As I am directly getting updates from master so why this happens.

How can we handle this in an effective manner so that there is no data loss on the slave.I do not want to set up the whole replication again for maintaining the data integrity.

Thanks..!