Certificate Autoenrollment

Hello,

I've setup a group policy to autoenroll machine certificates to the
computers in an OU. I can see from the certificate authority and the machines
themseleves the certificates are being issued, but the following error keeps
appearing in the client machines system log:

Event Type: Error
Event Source: Schannel
Event Category: None
Event ID: 36870
Date: 14/05/2008
Time: 09:16:18
User: N/A
Computer: Laptop101
Description:
A fatal error occurred when attempting to access the SSL server credential
private key. The error code returned from the cryptographic module is
0x80090016.

For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

I've done quite a bit of searching on the internet and I can only find
information that applies to server platforms not XP. Some people have found
its an issue with the NTFS permissions on the MachineKeys folder but the
client machines in the OU are clean builds.

If anyone could give me some help it would be great.

Thanks
Andrew