[Samba] Samba 3.0.10 - Invalid Value!!!

[Niatross]

I have a Macintosh Xserve running OS 10.4.8 and it's running Samba 3.0.10.
Everytime a Windows XP workstation logs off the Macintosh Xserve server, the
following shows up in the log.smbd (located at var/log/samba):

[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] pdb_ods.c:make_a_mod(2045)
 make_a_mod: INVALID VALUE!!!
[2007/01/11 14:24:17, 0] 
/SourceCache/samba/samba-100.5/samba/source/rpc_server/srv_util.c:get_alias_user_groups(206)
 get_alias_user_groups: gid of user Bob doesn't exist. Check your 
/etc/passwd and /etc/group files

My question is:

Why is this happening and how can I resolve it so that my log does not fill
up with these mesages everytime a user logs off the server. I have noticed
these log entries occur no matter who logs off the server.

I have run testparm smb.conf and receive only this error message:

Load smb config files from smb.conf
Processing section "[netlogon]"
Processing section "[homes]"
Processing section "[Shared]"
Processing section "[Home]"
Processing section "[Public]"
Processing section "[profiles]"
Loaded services file OK.
Invalid combination of parameters for service homes.
 Level II oplocks can only be set if oplocks are also set.
Invalid combination of parameters for service Shared.
 Level II oplocks can only be set if oplocks are also set.
Invalid combination of parameters for service Home.
 Level II oplocks can only be set if oplocks are also set.
Invalid combination of parameters for service Public.
 Level II oplocks can only be set if oplocks are also set.

What could be causing the "INVALID VALUE!!!" messages above?

Thanks, Niatross