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

> expdp schemas=...... dumpfile=.........

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORA-39006: internal error
ORA-39213: Metadata processing is not available

Solution:

SQL> execute sys.dbms_metadata_util.load_stylesheets;