ORA-31623: a job is not attached to this session via the specified handle

Yesterday did the impdp on our Exadata:

[oracle@ed02dbadm01 fns]$ cat imp.par 

[oracle@ed02dbadm01 fns]$ cat imp.par

userid=yu/yu

directory=fns

sqlfile=ddl.sql

job_name=yu

EXCLUDE=USER:" in ('SYS','SYSTEM','OUTLN','ORDDATA','OLAPSYS','MDDATA','SYSMAN','MGMT_VIEW','FLOWS_FILES','APEX_PUBLIC_USER','APEX_030200','OWBSYS','OWBSYS_AUDIT','SCOTT') "

LOGTIME=ALL

Import not worked, the import log :

Import: Release 12.1.0.1.0 - Production on Thu Aug 7 18:06:21 2014

UDI-31623: operation generated ORACLE error 31623

ORA-31623: a job is not attached to this session via the specified handle

ORA-06512: at "SYS.DBMS_DATAPUMP", line 3874

ORA-06512: at "SYS.DBMS_DATAPUMP", line 5161

ORA-06512: at line 1

Alert log :

Thu Aug 07 17:55:48 2014

DW00 started with pid=197, OS id=57824, wid=1, job YU.YU

Shared IO Pool defaulting to 512MB. Trying to get it from Buffer Cache for process 57824.

Thu Aug 07 17:55:56 2014

opidrv aborting process DM00 ospid (57808) as a result of ORA-447

The solution was found in Internet, the MOS have no information about this error:

[oracle@ed02dbadm01 fns]$ set|grep NLS

NLS_DATE_FORMAT='DD.MM.YYYY HH24:MI:SS'

[oracle@ed02dbadm01 fns]$ export NLS_DATE_FORMAT='YYYYMMDD HH24:MI'

This solution works !