Reports AWR oracle 11g

Hi,

I can´t generate AWR reports.

SQL> select * from DBA_HIST_WR_CONTROL;

      DBID
----------
SNAP_INTERVAL
---------------------------------------------------------------------------
RETENTION
---------------------------------------------------------------------------
TOPNSQL
----------
 881201471
+00000 01:00:00.0
+00008 00:00:00.0
DEFAULT

SQL> show parameter STATISTICS_LEVEL;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
statistics_level                     string      TYPICAL

SQL> exec dbms_workload_repository.create_snapshot;
BEGIN dbms_workload_repository.create_snapshot; END;

*
ERROR at line 1:
ORA-13516: AWR Operation failed: only a subset of SQL can be issued
ORA-06512: at "SYS.DBMS_WORKLOAD_REPOSITORY", line 99
ORA-06512: at "SYS.DBMS_WORKLOAD_REPOSITORY", line 122
ORA-06512: at line 1