Expdp Error

Hello,

version oracle 11.2
SO: windows 2003 server

expdp usuario/pass@BD schemas=usuario DIRECTORY=BACKUP DUMPFILE=usuario.dmp ENCRYPTION_PASSWORD="pass" logfile=log

I have done the expd, it worked ok, but one day show me this error:


ora-39001 invalid argument value

ora-01775 looping chain of synonyms

I don't know why happened it, The user hasn't synonyms:

select * from dba_synonyms
where owner='USUARIO';

This query for my user don't show records.

Thanks.