samba - Sep 2003 - samba passwords gone haywire since upgrade (3.0.0-1)

hi all,

i was running the previous RPM (samba-2.2.8a-2_rh73.i386.rpm) and have just
upgraded to the 3.0.0-1. everything seemed to go smoothly. 

when I try to mount my media share from my other linux box, I get the
following error:
1639: tree connect failed: ERRSRV - ERRbadpw (Bad password - name/password
pair in a Tree Connect or Session Setup are invalid.)

I'm still running against my old smb.conf. I've run through the new one
smb.conf.rpm (or whatever) and ammended it to match my configuration - and I
get the identical results.

I'm running share level security.

when I check the %m log file, I see this, which looks wrong:
[2003/09/25 14:54:50, 5] lib/username.c:Get_Pwnam(288)
  Finding user merlot
[2003/09/25 14:54:50, 5] lib/username.c:Get_Pwnam_internals(223)
  Trying _Get_Pwnam(), username as lowercase is merlot
[2003/09/25 14:54:50, 5] lib/username.c:Get_Pwnam_internals(239)
  Trying _Get_Pwnam(), username as uppercase is MERLOT
[2003/09/25 14:54:50, 5] lib/username.c:Get_Pwnam_internals(247)
  Checking combinations of 0 uppercase letters in merlot
[2003/09/25 14:54:50, 5] lib/username.c:Get_Pwnam_internals(251)
  Get_Pwnam_internals didn't find user [merlot]!

you will notice below, on my machine called merlot, I am specifying user
"media" - why is it looking for user merlot?

[root@merlot shiraz]# cat /bin/mount_media
smbmount //shiraz/media /mnt/shiraz/ -o username=media

also, in samba.log I'm getting:
[2003/09/25 14:56:49, 5] passdb/pdb_interface.c:make_pdb_methods_name(455)
  pdb backend smbpasswd has a valid init
[2003/09/25 14:56:49, 5] passdb/pdb_interface.c:make_pdb_methods_name(431)
  Attempting to find an passdb backend to match guest (guest)
[2003/09/25 14:56:49, 5] passdb/pdb_interface.c:make_pdb_methods_name(452)
  Found pdb backend guest
[2003/09/25 14:56:49, 5] passdb/pdb_interface.c:make_pdb_methods_name(455)
  pdb backend guest has a valid init

why is it trying to use the guest user?

my smb.conf on the share reads as follows:
[homes]
   comment = Home Directories
   browseable = no
   writable = yes
   valid users = %S
   create mode = 0664
   directory mode = 0775

any suggestions would help.