samba - Feb 2007 - File transfers to Windows XP x64 stalling and dying after a few minutes.

I just did a fresh install of Windows XP Professional x64 on my primary
machine, and am reconnecting all of my LAN services.  One thing I have on my
home network is a dedicated file server, running Ubuntu and Samba, used as a
general file server, as well as a backup for when I reformatted my main
system.

While attempting to restore some of my files, I started noticing some odd
errors.  After a few minutes of transfers on a Samba session, the transfers
would simply die, with various errors.  Watching movies or listening to
music stored on the server would meet with similar problems (the audio/video
would start to skip).

I attempted to narrow down the problem a bit.  I have not experienced any
errors with Internet transfers at all - I receive sustained high transfer
rates off of high-traffic websites, and get excellent ping rates when
playing on-line games.   Transfers on the LAN using other protocols (SCP,
AIM, etc.) all work just fine, both to and from the server, as well as with
other machines on the LAN.

My only conclusion was that something in Samba was causing this issue.  To
confirm, I watched the samba log and the top monitor while a transfer was
occurring (and failed).  Sure enough, something strange happened.

I opened up the shared folder in Windows and began a copy of a large (2 Gb)
ISO file.  At first, the transfer went just fine.  But then, the smbd
process went from a steady 40% CPU utilization down to next to nothing.  The
file transfer also stalled at this point.  After about 30 seconds, the
process went back to normal utilization and the file transfer resumed, but
the stall happened again after another few minutes.

At this point, Windows apparently gave up, saying that "The specified
network name can no longer be found" and aborted the file transfer.  Then,
the log spit out a few errors, which I have reproduced here:

[2007/02/12 14:55:08, 1] smbd/service.c:make_connection_snum(693)
  bast (192.168.0.102) connect to service dump initially as user neppyman
(uid=1000, gid=1000) (pid 11290)
[2007/02/12 15:01:29, 0] lib/util_sock.c:read_data(529)
  read_data: read failure for 4 bytes to client 192.168.0.102. Error Connection
reset by peer
[2007/02/12 15:01:29, 0] lib/util_sock.c:write_data(557)
  write_data: write failure in writing to client 192.168.0.102. Error Broken
pipe
[2007/02/12 15:01:29, 0] lib/util_sock.c:send_smb(765)
  Error writing 75 bytes to client. -1. (Broken pipe)
[2007/02/12 15:01:31, 1] smbd/service.c:make_connection_snum(693)
  bast (192.168.0.102) connect to service dump initially as user neppyman
(uid=1000, gid=1000) (pid 11311)

I'm certainly no Linux guru, but I was at least able to get Samba set up and
running prior to the reformat, and had no issues with it up until this
point.

Here are various portions of my smb.conf file:

[global]
   workgroup = DOPE FIENDS
   server string = Loki
   dns proxy = no
   log file = /var/log/samba/log.%m
   max log size = 1000
   syslog = 0
   panic action = /usr/share/samba/panic-action %d

   security = user
   encrypt passwords = true
   valid users = <snip> ... neppyman
   passdb backend = tdbsam guest

   obey pam restrictions = yes
   invalid users = root

   passwd program = /usr/bin/passwd %u
   passwd chat = *Enter\snew\sUNIX\spassword:* %n\n
*Retype\snew\sUNIX\spassword:* %n\n .
   wins support = no

[homes]
   comment = Home Directories
   browseable = no
   writable = no
   create mask = 0700
   directory mask = 0700

[printers]
   comment = All Printers
   browseable = no
   path = /tmp
   printable = yes
   public = no
   writable = no
   create mode = 0700

[print$]
   comment = Printer Drivers
   path = /var/lib/samba/printers
   browseable = yes
   read only = yes
   guest ok = no

[dump]
   path = /share
   comment = Network Dump
   read only = No
   force create mode = 0777
   guest ok = Yes

(end smb.conf)

Version information:
Server OS:  Ubuntu 6.06 LTS, fully patched.
Samba:  3.0.22
Host OS:  Windows XP x64, fully patched

Any ideas as to what could be causing this and how it can be fixed?  And if
you need more information, just let me know.

-- Geoff