Micro Reiniciando.....banco oracle

Tenho um banco de dados Oracle 8, e existe alguns momentos este
servidor esta reiniciando
abri o log...e tem a seguinte mensagem:
Fatal NI connect error 12637,
connecting to:
(LOCAL=NO)

VERSION INFORMATION:

TNS for NetWare:
Version 8.1.6.0.0 -
Production

TLI/SPX/IPX NT Protocol Adapter for NetWare:
Version 8.1.6.1.0 -
Production
Oracle
Bequeath NT Protocol Adapter for NetWare:
Version 8.1.6.1.0 - Production

Time: 03-MAY-2004 11:57:19

Tracing not turned on.

Tns error struct:
nr err code: 0

ns main err code: 12637

TNS-12637: Packet receive failed

ns secondary err code: 0

nt main err code: 0

nt secondary err code: 0


Alguem pode me dar uma luz..
Desde ja agradeco
Evandro