ORA-39006: internal error; ORA-39213: Metadata processing is not available;

Oracle 11.2.0.3 - 64 bit on Windows

When using IMPDP you get the error :

ORA-39006: internal error

ORA-39213: Metadata processing is not available

Workaround 

sqlplus / as sysdba

SQL> execute sys.dbms_metadata_util.load_stylesheets;