Assuming the roaming profiles are working (and the server share where the
roaming profiles are located has appropriate read/write permissions) it does
sound like some type of DNS issue. Because it happens during EVERY logon
(and not just the first logon) it points more toward a DNS or
server-resource issue and not a profile-specific issue.
If this is a DNS issue, if you were to logon with an account that does NOT
use roaming profiles, the delay would still be evident; that could be a
simple test. If the 'administrator' logons on to the server itself, is the
delay evident? Does the Event Viewer on the server contain any relevant
issues which may indicate the problem? I assume the clients and server are
on the same subnet without any routers/firewalls between them. If there have
been any type of security restrictions (firewall, ACL, etc) between the
client and server - check these as well as I've seen this behavior when
Access Control Lists on routers are too restrictive and block some of the
required ports clients require for roaming profiles to operate.
When the delay occurs, at what point during logon does the delay occur; 1)
when you first type in the username/password and click Ok but before you see
any other dialog box, or 2) during 'loading system settings', or 3) when the
systems is 'applying security policy' (at least, I think that's the
sequence).