samba - Sep 2003 - can't change password : PANIC failed to set gid

Hi !

When trying to change users password from NT or XP workstations (using 
CTRl-ALT-DEL), I get an error under Windows and this in my samba logs:

Sep 10 16:15:08 testbox kernel: pid 2709 (smbd), uid 10000: exited on 
signal 6
Sep 10 16:15:08 testbox smbd[2709]: [2003/09/10 16:15:08, 0] 
lib/util_sec.c:assert_gid(114)
Sep 10 16:15:08 testbox smbd[2709]:   Failed to set gid privileges to 
(0,10000) now set to (10000,10000) uid=(0,10000)
Sep 10 16:15:08 testbox smbd[2709]: [2003/09/10 16:15:08, 0] 
lib/util.c:smb_panic(1094)
Sep 10 16:15:08 testbox smbd[2709]:   PANIC: failed to set gid
Sep 10 16:15:08 testbox smbd[2709]:
Sep 10 16:15:08 testbox smbd[2709]:
Sep 10 16:15:08 testbox kernel: pid 2710 (smbd), uid 10000: exited on 
signal 6
Sep 10 16:15:08 testbox smbd[2710]: [2003/09/10 16:15:08, 0] 
lib/util_sec.c:assert_gid(114)
Sep 10 16:15:08 testbox smbd[2710]:   Failed to set gid privileges to 
(0,10000) now set to (10000,10000) uid=(0,10000)
Sep 10 16:15:08 testbox smbd[2710]: [2003/09/10 16:15:08, 0] 
lib/util.c:smb_panic(1094)
Sep 10 16:15:08 testbox smbd[2710]:   PANIC: failed to set gid
Sep 10 16:15:08 testbox smbd[2710]:
Sep 10 16:15:08 testbox smbd[2710]:
Sep 10 16:15:08 testbox smbd[2711]: [2003/09/10 16:15:08, 0] 
lib/util_sec.c:assert_gid(114)
Sep 10 16:15:08 testbox smbd[2711]:   Failed to set gid privileges to 
(0,10000) now set to (10000,10000) uid=(0,10000)
Sep 10 16:15:08 testbox smbd[2711]: [2003/09/10 16:15:08, 0] 
lib/util.c:smb_panic(1094)
Sep 10 16:15:08 testbox smbd[2711]:   PANIC: failed to set gid
Sep 10 16:15:08 testbox smbd[2711]:
Sep 10 16:15:08 testbox smbd[2711]:
Sep 10 16:15:08 testbox kernel: pid 2711 (smbd), uid 10000: exited on 
signal 6
Sep 10 16:15:08 testbox kernel: pid 2712 (smbd), uid 65534: exited on 
signal 6
Sep 10 16:15:08 testbox smbd[2712]: [2003/09/10 16:15:08, 0] 
lib/util_sec.c:assert_gid(114)
Sep 10 16:15:08 testbox smbd[2712]:   Failed to set gid privileges to 
(0,65534) now set to (65534,65534) uid=(0,65534)
Sep 10 16:15:08 testbox smbd[2712]: [2003/09/10 16:15:08, 0] 
lib/util.c:smb_panic(1094)
Sep 10 16:15:08 testbox smbd[2712]:   PANIC: failed to set gid
Sep 10 16:15:08 testbox smbd[2712]:
Sep 10 16:15:08 testbox smbd[2712]:
Sep 10 16:15:08 testbox kernel: pid 2713 (smbd), uid 65534: exited on 
signal 6
Sep 10 16:15:08 testbox smbd[2713]: [2003/09/10 16:15:08, 0] 
lib/util_sec.c:assert_gid(114)
Sep 10 16:15:08 testbox smbd[2713]:   Failed to set gid privileges to 
(0,65534) now set to (65534,65534) uid=(0,65534)
Sep 10 16:15:08 testbox smbd[2713]: [2003/09/10 16:15:08, 0] 
lib/util.c:smb_panic(1094)
Sep 10 16:15:08 testbox smbd[2713]:   PANIC: failed to set gid
Sep 10 16:15:08 testbox smbd[2713]:
Sep 10 16:15:08 testbox smbd[2713]:
Sep 10 16:15:08 testbox kernel: pid 2714 (smbd), uid 65534: exited on 
signal 6
Sep 10 16:15:08 testbox smbd[2714]: [2003/09/10 16:15:08, 0] 
lib/util_sec.c:assert_gid(114)
Sep 10 16:15:08 testbox smbd[2714]:   Failed to set gid privileges to 
(0,65534) now set to (65534,65534) uid=(0,65534)
Sep 10 16:15:08 testbox smbd[2714]: [2003/09/10 16:15:08, 0] 
lib/util.c:smb_panic(1094)
Sep 10 16:15:08 testbox smbd[2714]:   PANIC: failed to set gid
Sep 10 16:15:08 testbox smbd[2714]:
Sep 10 16:15:08 testbox smbd[2714]:

Do you have any idea what could cause this ?
I didn't set the "unix password sync" option yet, so the problem
does
not comes from there.
I'm using FreeBSD-5.1+samba-2.2.8a (with Unix accounts, no ldap).

Thanks in advance for your help.
Regards,

Antoine