Transaction isolation

[admin]

Hi all,
we have a problem with a job that reads from an Oracle table and writes to another one after having tested two lookups. The update action used is User-Defined SQL containing an update statement inside. The job reads 26000 records and the Array size and Transaction isolation are both set to 32000. If we run the job, it reads and writes all but always stays in a running mode such as it is waiting to close something. In fact looking on DBA Studio the Oracle sessions tied to that Datastage job, they are all actives. Have you any idea about this problem? DataStage version is 4.1.1, the platform is a Compaq thru64.
Thanks a lot
Patrizia