ORA-27038: created file already exists

Hi I am planing to backup the DB offlne (mount mode) and  failed  will following error.  backup location is empty.  not sure why .

RMAN> catalog start with '/orabkp/oradata/PRD/rman/bkp_sets';

searching for all files that match the pattern /orabkp/oradata/PRD/rman/bkp_sets

no files found to be unknown to the database

RMAN> run{

2> backup  check logical   database;

3> backup current controlfile format '/orabkp/oradata/PRD/rman/bkp_sets/%d_ctrl_%s_20190809111424';

4> }

channel ORA_DISK_4: starting piece 1 at 09-AUG-19

RMAN-03009: failure of backup command on ORA_DISK_1 channel at 08/09/2019 11:15:29

ORA-19504: failed to create file "/orabkp/oradata/PRD/rman/bkp_sets"