Dropped users on AIX 5.1

We are experiencing an issue where 4gl programs (4js) are exiting with no error logging of any kind. The processes just die. This is happening to all user processes that have a database connection, although our menu program (Which has no database connection is not dying) Informix's crontab runs onmode -F every 10 minutes. Is this the possible cause of the problem. I am going to remove the crontab entry and modify the shared memory paramaters in onconfig, however has anyone come across a similar problem. Informix Dynamic Server Version 9.30.UC3 Four J's Dynamic Virtual Machine Version 3.50.01.05 Built Jul 10 2002 15:43:06 (c) 1989-2002 Four J's Development Tools Ltd Language support library: Standard ASCII (ISO8859-1) Database front end : INFORMIX ESQL/C 9.xx Thanks in advance Steve Weet