[Samba] Problem with Samba 3.0.10 as PDC & WinXP clients

[PaLo]

Hi, I’m using Samba 3.0.10 as PDC & LDAP as users data base. Clients are 
Windows XP and I’m having problems with network drive disconections. I 
map a network drive, and some time later, it appears as disconnect. When 
I click to acces, the network drive has no problem about connecting 
again, but I don’t understand why the disconection occurs. In the log 
file appears this:

smbd/service.c:close_cnum(841)
clientxp1 (xxx.xxx.xxx.xxx) closed connection to service xxxx

I would like to know if any of you know something about this, or have 
had this kind of problems…
Thanks