[Samba] Poor perfomance Samba 3.0 + DBF/PX

[Sebastian Davancens]

Im running a linux fiel server with RH 8.0 and Samba,
acting as a PDC. 40 clients (Win98/2000) use an application 
that is based on Foxpro and Paradox tables, which are stored 
in the server (Contabilidad and CRT shares).
The problem is the following: with samba 2.2.8, everything worked fine. 
But when we updated to 3.0.2a, the perfomance dicreased a lot. Its really
slow. Apart from that, the .dbf files started to corrupt oftenly.
The smb.conf has not been changed.
Why is this happening??
Here i post a part of my smb.conf file:

[global]

        socket options = TCP_NODELAY IPTOS_LOWDELAY
SO_SNDBUF=8192 SO_RCVBUF=8192
	domain master = Yes
        encrypt passwords = Yes
        logon home = \\%L\%U
        server string = Samba PDC running %v
        logon script = login.bat
        veto oplock files =
/*.dbf/*.DBF/*.cdx/*.CDX/*.db/*.DB/*.Y??/*.y??/*.XG?/*.xg?/*.MB/*.mb/*.VAL/*.val/*.PX/*.px/*.mdb/*.MDB/*.lck/*.LCK/
        workgroup = SMBAR
        logon path = \\%L\profiles\%U
        os level = 64
        directory mask = 0770
        printcap name = /etc/printcap
        preferred master = Yes
        domain admin group = @admins
        domain logons = Yes
        log level = 1

[homes]
        comment = Home Directories
        force group = admins
        read only = No
        force create mode = 0770
        browseable = No

[profiles]
        path = /home/samba/profiles
        read only = No
        create mask = 0600
        directory mask = 0700
        browseable = No

[netlogon]
        comment = Network Logon Service
        path = /home/netlogon
        write list = @admins
        browseable = No
        browseable = No


[CRT]
        comment = CRT
        path = /home/captacion/tmkt
        admin users = @admins
        write list = @admins, @gr_crt
        force group = gr_crt
        create mask = 0775
        force create mode = 0775
        browseable = No
        dont descend = contabilidad ccvd

[contabilidad]
        comment = contabilidad
        path = /home/captacion/tmkt
        admin users = @admins
        read list = @admins, @gr_crt
        write list = @gr_contabilidad
        force group = gr_contabilidad
        browseable = No
        dont descend = crt

One last note: we have already tried with level2 oplocks = false 
and kernel oplocks = false, but it was useless
Thanks in advance,
Sebastian