When using the AllowAccess method of either the File or Folder objects, you cannot specify the domain of a valid group account:
oFolder.AllowAccess "MyDomain\Everyone", 1024

Error Type: 
    FileMgr.Folder.1 (0x80020009) 
    No mapping between account names and security IDs was done. 

If the group account is specified without the domain,...
oFolder.AllowAccess "Everyone", 1024

...you will not receive a run-time error. However if multiple domains containing a group with this name are available, the domain for this group acccount will be assigned at random.

1. If the group account being specified only exists on one domain, use the AllowAccess method without specifying the domain. This will prevent a run-time error:
   oFolder.AllowAccess "myGroup", 1024
   
   
2. If the group account is a name that is used on mutiple domains, then you must specify the domain controller. Do this by providing the fully qualified domain name of the domain controller, the local machine or member server in the AccountServer property of the folder or file on which you are trying to grant access.
   oFolder.AccountServer = "DC10.internal.MyDomain.com"
   oFolder.AllowAccess "myGroup", 1024
   

• Permissions required for AllowAccess: http://support.softartisans.com/kbview.aspx?ID=883
  
  
• How to specify the correct name for the Account Server property: http://support.softartisans.com/kbview.aspx?ID=882