If an administrator users Microsoft User Manager to modify a user account, the 
account becomes disabled.  I have noticed that Samba 3.0.3 
adds "sambaKickoffTime: 0" to the LDAP account for the user.  If you give the 
account a expiration date in the Account Information section of User Manager 
instead of 'Never' the account is ok.  It seems when trying to make the account 
never expire, Samba 3.0.3 puts 0 for the sambaKickoffTime attribute instead of 
2147483647.  Previous versions did not modify/add this attribute.