Meaning of these errors?

[Steve Snyder]

While looking through my Samba (v2.0.10, running on Linux v2.4.10) log, I 
noticed these errors:

# cat /var/log/samba/smb.log.1
[2001/10/04 11:08:36, 0] lib/util_sock.c:set_socket_options(151)
  Failed to set socket option SO_KEEPALIVE (Error Bad file descriptor)
[2001/10/04 11:08:36, 0] lib/util_sock.c:set_socket_options(151)
  Failed to set socket option IPTOS_LOWDELAY (Error Bad file descriptor)
[2001/10/04 11:08:36, 0] lib/util_sock.c:set_socket_options(151)
  Failed to set socket option TCP_NODELAY (Error Bad file descriptor)

There are only 2 occurances of this set of errors in a month of Samba logs. 
 The dates and times of these errors don't suggest anything unusual 
happening on my network on these occasions.

Anyone know the cause and/or cure of these errors?

Thanks.