I was working on moving a group of users to a new Windows Server 2008 domain. I had copied all the users profiles to the new server. Whenever I tried logging in with a roaming profile, on a Windows XP client, it would get an error and load a local default profile. I found that when using Windows XP clients on a  2008 domain, roaming profiles will not recognize the presents of a version 1 profile (Windows XP, 2000, 2003) without the presents of a version 2 (Windows Vista, 7, 2008) user profile. In order to resolve the issue I logged onto the domain controller  as one of the users which initiated the creation of a version 2 profile for that user. I then modified the permissions and use it as a default profile and copied it to all the other users profile folders. This meant that all user then had a “NTProfile” and “NTProfile.V2” folder in the profile path. I then logged into a Windows XP client and it loaded the version 1 profile without  any problems.