samba - Feb 2005 - Inconsistant write access to SAMBA share

Running Redhat 2.4.21 with Samba 3.0.9.  My share is readable ok but 
while write access will work when i've booted from a dos environment 
(Bart's boot Disk http://www.nu2.nu/bootdisk/ which is a marvelous free 
product that i'm happy to plug)  When i authenticate from a windows XP 
or 2000 desktop i can read but have no write access with the same 
account.  The folder permissions all seem to match my windows user and 
windows group and i'm stumped as to why this all works from the dos 
prompt but not from windows.  Any ideas?

Here is my smb.conf config

[global]

   workgroup = MYDOMAINNAME
   netbios name = MYSERVERNAME
   realm = MYDOMAINNAME.MY.DOMAIN
   security = ads
   encrypt passwords = yes
   password server = MY_ADDC.MY.DOMAIN
   wins server = MY_ADDC.MY.DOMAIN
   name resolve order = lmhosts host wins bcast
   log file = /var/log/samba/%m.log
   server string = RedHat Samba Server
   log level = 2
winbind cache time = 10
winbind enum users = yes
winbind enum groups = yes
template shell = /bin/bash
template homedir = /home/%D/%U
idmap uid = 10000-50000
idmap gid = 10000-20000

#============================ Share Definitions 
=============================# A publicly accessible directory, but read only,
except for staff

[SubShare1]
   path = /data/RootShare/SubShare1
   browseable = no
   read only = no
   write list = @techs
   read list = @ausergroup

[SubShare2]
   path = /data/RootShare/SubShare2
   browseable = no
   read only = no
   write list = @techs, @mitsadmin
   read list = @techs, serviceaccount

[SubShare3]
   path = /data/RootShare/SubShare3
   browseable = no
   read only = no
   write list = @techs
   read list = @techs

 [SubShare4]
   path = /data/RootShare/SubShare4
   browseable = no
   read only = no
   write list = @administrators, @mitsadmin

[RootShare]
   path = /data/RootShare
   browseable = no
   read only = @techs
   write list = @administrators