Ok, here is the solution...thanks to me for my help...

BEGIN
SYS.DBMS_STATS.EXPORT_SCHEMA_STATS ('POWNER',
'FULL_PROD_STATS',
NULL,
USER);
END;

> -- Problem occurs here...
> BEGIN
> SYS.DBMS_STATS.EXPORT_SCHEMA_STATS ('POWNER',
> 'MK.FULL_PROD_STATS');
> END;