expdp result EXP-00056 , ORA-01555 ORA-22924

Hello
Release 10.2.0.3.0

By exporting a table ATTACHMENTDATA with DATA(BLOB) field  with 72586 records (select count(*) from opin.ATTACHMENTDATA)

exp system@ora40 buffer=10000000 FILE=opin.dmp owner=OPIN compress=no log=exp_opin.log
....
i'm  getting
 . . exporting table                 ATTACHMENTDATA
EXP-00056: ORACLE error 1555 encountered
ORA-01555: snapshot too old: rollback segment number  with name "" too small
ORA-22924: snapshot too old

DOC ID 787004.1 indicate how to find corrupt_rowid but after apply teh notice nothing is found.
the CORRUPT_LOBS table is empty .

could you please help to investigate the problem thanks