During an ETL job sometimes bad data will sneak into your OLTP and needs to be searched out. You can adjust the step limit by querying the R_STEP table and then updating the associated row in the R_STEP_ATTRIBUTE table:

To acquire the id_step for the r_step_attribute update:
sql> select id_step from r_step where name = 'your_stepname';

To update the limit (X = step limit, Y = id_step from above):
sql> update r_step_attribute set value_num=X where id_step=Y and code='limit';

Tip based on the ETL toolkit found at http://kettle.pentaho.org/.

Thanks to McG for the tip.

Run the following query:

SELECT s.username, s.program, s.logon_time
FROM v$session s, v$process p, sys.v_$sess_io si
WHERE s.paddr = p.addr(+)
AND si.sid(+) = s.sid
AND s.type = 'USER';