unable to import AWR for a capture workload

SQL> select dbms_workload_capture.import_awr(1,'SYSTEM') from dual;

select dbms_workload_capture.import_awr(1,'SYSTEM') from dual

*

ERROR at line 1:

ORA-20113: Table WRM$_DATABASE_INSTANCE already exists in schema SYSTEM

ORA-06512: at "SYS.DBMS_WORKLOAD_CAPTURE", line 1826

ORA-06512: at line 1

when i try to get capture report:

ERROR:

ORA-20222: Invalid Input. AWR data not found. Please import the capture's AWR snapshots using DBMS_WORKLOAD_CAPTURE.IMPORT_AWR() prior to generating the

capture report.

ORA-06512: at "SYS.DBMS_WORKLOAD_CAPTURE", line 1329

CAPTURE_ID NAME                 DIRECTORY                      STATUS                                   START_TIM END_TIME  AWR_EXPORTED
---------- -------------------- ------------------------------ ---------------------------------------- --------- --------- ------------