Answer
That kind of fatal-error message is typically referring to the application server's own J2EE alert log, not the Oracle database alert log — found at <IFS_HOME>\instance\<InstanceID>\logs\j2ee\ on the application server host. That same logs folder also holds other relevant log files (like the ifsapp log and batch processor log), worth checking together since the real underlying exception detail is often split across more than one of them rather than appearing in a single obvious place.