Unknown system error

[JasonU]

Hello

I have recieved the following error off of a Domino 653 server:

Database Title: Media24 Ltd 2006 Interim Audit
Database ReplicaID: 4225708900276A74
Details: #257 Unknown OS error

<===== D E T A I L S =====>

Client Name: Media24 Ltd
File Name: Engment.nsf
File Path: MyClients/CapeTown/030369/30_09_2005/030369
S.W. Version: MyClient 1.3.1 Client Work File - Local GAAS or ISA
Title: Media24 Ltd 2006 Interim Audit
Replica ID: 4225708900276A74
Primary Server: ZA-CPTGEN001/ZA/SERVER/PWC


Im more interested in this error: "Details: #257 Unknown OS error"

Has anyone seen such an error before? The think tank think its a microsoft O/S error. Any more ideas that could be investigated?

Thanks
Jase