Unable to write on server OES

We encoutered a problem with OES SP2

Client were unable to write data on server
Server is very slow
unable to acces via SSH, VNC


and obtain multiple messages in log :

# smbd[17237]: [2007/12/11 09:34:30, 0] lib/util_sock.c:write_data(554)
# smbd[17237]: write_data: write failure in writing to client
192.168.1.40. Error Connection reset by peer
# smbd[17237]: [2007/12/11 09:34:30, 0] lib/util_sock.c:send_smb(762)
# smbd[17237]: Error writing 4 bytes to client. -1. (Connection reset by
peer)
# kernel: Couldn't get FDN from LUM for uid, rc=630 = -1

I try log message in knowledgebase without result.

After restarting the server, the problem not persist

Does anyone have explaination about this problem and how to resolv it in
the futur