Vista - Vista VPN connect hangs at "verifying user name and password"

I'm having a problem with a Vista Home Premium system. When I attempt to
connect to an Win2k3 RRAS system, the Vista laptop occasionally connects and
works fine, but most of the time it hamgs at "verifying user name and
password" and times out. I see a couple of different error messages on the
client -- there is a 619 error and other times I receive an 806. I know it is
a problem with the Vista laptop and not a server or network problem because I
can connect to the RRAS server with other systems (including another Vista
laptop) from this network using the same username and password.

I have also checked and double checked the connection properties and they
are the same as the system that connects with no problems, including both
using the "typical" security settting.

I see nothing about this on the server's event logs, the connection doesn't
seem to progress far enough to generate any errors.

I uninstalled a couple of things including a program called Rasadmin that
the user installed on the system. It may still be a conflict with some
program but if it is, it is nothing that is apparent to me. I also tried
disabling the Windows Firewall, with (again) no result.

I did turn on RAS tracing and I tried looking through some of those logs but
I didn't find anything that seemed "off".

Any help would be appreciated.

Thanks...