Oracle and Windows 2000

Oracle 816 windows 2000
In the o/s event log there are warnings saying
'Instance FIMS terminated abnormally'.

Please can someone help me understand as to why this could be happening while the database is running fine.
No error messages in the alert log.

Thanks

I think 8.16 is not certified on 2000, only 8.17 and up versions are certified on 2000 platform.