ORA-01555 on DYNPSOURCE during SAP system export

Dears

(RTF) ########## WARNING ###########

        Without ORDER BY PRIMARY KEY the exported data may be unusable for some databases

(DBC) Info: No commits during lob export

DbSl Trace: ORA-01555 occurred when reading from a LOB

(EXP) ERROR: DbSlLobGetPiece failed

  rc = 99, table "DYNPSOURCE"

  (SQL error 1555)

  error message returned by DbSl:

ORA-01555: snapshot too old: rollback segment number  with name "" too small

ORA-22924: snapshot too old

(DB) INFO: disconnected from DB

The same error occurs with R3load, Oracle EXP, R3trans

I tried enlarging PSAPUNDO, PSAPTEMP and changing undo_retention, lob segement PCTVERSION

Each time at around 1.500 million logical reads the export fails with the exact same file size:

100105216 DYNPSOURCE.001

SQL> select table_name, segment_name, pctversion, retention

from dba_lobs where table_name in ('  2  DYNPSOURCE');

TABLE_NAME                     SEGMENT_NAME                   PCTVERSION

-

-

-

RETENTION

-

DYNPSOURCE                     SYS_LOB0000296057C00004$$

     43200

DYNPSOURCE                     SYS_LOB0000296057C00005$$

     43200

DYNPSOURCE                     SYS_LOB0000296057C00006$$

     43200

Anyone has any ideas how to solve this issue.

In meantime I keep on searching and I'll post updated on issue.

Kind regards

Tom