[Samba] Network problem (?)

[Janos Dohanics]

I have a Win XP client which is connecting to a samba-3.3.7 server running on 
FreeBSD 7.2-STABLE through openvpn-2.0.6_9.

The client can connect, browse folders, and transfer files. However, random 
error messages keep popping up, such as "The network name is no longer 
available", or "File is used by another application". Sometimes, after a long 
wait, the folder opened on the Samba drive closes unexpectedly.

Can't find anything obviously wrong in Samba logs.

I tried to replicate these problems by using a different Win XP computer which 
connects to the same server through OpenVPN using the same user account. None 
of the problems described occurred. There are also no such problems with Win 
XP clients connecting on the LAN.

I have done packet capture; I noticed that there are many Retransmissions 
around the time when the error occurs. I have also noticed that the Win XP 
computer in question initiates transmissions on ports that are not obvious to 
me (e.g. tns-adv, dyna-access, mcns-tel-ret, and many others, which vary by 
session).

Searched the web about possible causes and solutions to the problem, I found 
the advice to change the NIC settings from Auto to 100/10 duplex/half 
duplex - I changed settings, no effect.

Could someone help me with this? I can provide configuration files and packet 
capture files.

-- 
Janos Dohanics