samba - Feb 2013 - Samba 4 DC log.smd flooded with Conversion error

My machine is running samba 4.0.3 inside a DomU of Debian Wheezy.

Following the Samba AD Howto and running Samba 4.0.3 successfully but with one
pretty serious problem.  When I try access the folder with 1000 files, the speed
is *VERY* slow.

After employ log level to 3, log.smbd is flooded with:
============================================[2013/02/09 23:44:05.910717,  3]
../source3/locking/share_mode_lock.c:408(fetch_share_mode_unlocked)
  Could not fetch share entry
[2013/02/09 23:44:05.911631,  3]
../source3/smbd/dir.c:1136(smbd_dirptr_get_entry)
  smbd_dirptr_get_entry mask=[*] found ./?? fname=?? (??)
[2013/02/09 23:44:05.912607,  3]
../lib/util/charset/convert_string.c:316(convert_string_handle)
  convert_string_internal: Conversion error: Illegal multibyte sequence(??)
[2013/02/09 23:44:05.913517,  3]
../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(???)
[2013/02/09 23:44:05.914467,  3]
../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(??)
[2013/02/09 23:44:05.915412,  3]
../lib/util/charset/convert_string.c:316(convert_string_handle)
  convert_string_internal: Conversion error: Illegal multibyte sequence(?)
[2013/02/09 23:44:05.916356,  3]
../lib/util/charset/convert_string.c:297(convert_string_handle)
  convert_string_internal: Conversion error: Incomplete multibyte sequence(??)
=================================================================
I have googled the mailing list and I am sure that the iconv library is
installed correctly and also pass the test for ACL in filesystem in linux listed
here
(https://wiki.samba.org/index.php/Samba_4/OS_Requirements#Testing_your_filesystem).
Also, the folder permission is 770 and owned by root:root.

Can anyone help?

smb.conf
=============# Global parameters
[global]
        workgroup = YAUOICHURCH
        realm = SAMBA4.YAUOI.ORG
        netbios name = FILE
        server role = active directory domain controller
        dns forwarder = 192.168.107.1
        log level = 2

[netlogon]
        path = /usr/local/samba/var/locks/sysvol/samba4.yauoi.org/scripts
        read only = No

[sysvol]
        path = /usr/local/samba/var/locks/sysvol
        read only = No

[printers]
        comment = All Printers
        path = /usr/local/samba/var/spool
        browseable = Yes
        read only = No
        printable = Yes

[print$]
        comment = Point and Print Printer Drivers
        path = /usr/local/samba/var/print
        read only = No

[profiles]
        path = /usr/local/samba/var/profiles
        read only = No

[Personal]
        path = /home/personal/
        read only = No

[Public]
        path = /home/group
        read only = No

============
Log level = 10 is as follows:
============http://kinglok.org/log.smbd
=============

On Sat, Feb 09, 2013 at 11:54:26PM +0800, Kinglok, Fong
wrote:
> My machine is running samba 4.0.3 inside a DomU of Debian Wheezy.
> 
> Following the Samba AD Howto and running Samba 4.0.3 successfully but with
one pretty serious problem.  When I try access the folder with 1000 files, the
speed is *VERY* slow.
> 
> After employ log level to 3, log.smbd is flooded with:
> ============================================> [2013/02/09
23:44:05.910717,  3]
../source3/locking/share_mode_lock.c:408(fetch_share_mode_unlocked)
>   Could not fetch share entry
> [2013/02/09 23:44:05.911631,  3]
../source3/smbd/dir.c:1136(smbd_dirptr_get_entry)
>   smbd_dirptr_get_entry mask=[*] found ./?? fname=?? (??)
> [2013/02/09 23:44:05.912607,  3]
../lib/util/charset/convert_string.c:316(convert_string_handle)
>   convert_string_internal: Conversion error: Illegal multibyte sequence(??)
> [2013/02/09 23:44:05.913517,  3]
../lib/util/charset/convert_string.c:297(convert_string_handle)
>   convert_string_internal: Conversion error: Incomplete multibyte
sequence(???)
> [2013/02/09 23:44:05.914467,  3]
../lib/util/charset/convert_string.c:297(convert_string_handle)
>   convert_string_internal: Conversion error: Incomplete multibyte
sequence(??)
> [2013/02/09 23:44:05.915412,  3]
../lib/util/charset/convert_string.c:316(convert_string_handle)
>   convert_string_internal: Conversion error: Illegal multibyte sequence(?)
> [2013/02/09 23:44:05.916356,  3]
../lib/util/charset/convert_string.c:297(convert_string_handle)
>   convert_string_internal: Conversion error: Incomplete multibyte
sequence(??)
> =================================================================
Is that filename '??' in utf8 format on the disk ?
Or is it in a previous encoding format such as big5 or
Guobiao ?

Without a parameter setting Samba defaults to utf8
encoding, and things can go wrong if filenames on
disk aren't actually utf8.

Jeremy.