Problem with the event "AD CS could not use the default provider for encryption keys"

Hi, 

My CA (Root Enterprise CA in Windows 2008 R2) reports the following error, 

Log Name:      Application
Source:        Microsoft-Windows-CertificationAuthority
Date:          13.06.2013 07:53:36
Event ID:      87
Task Category: None
Level:         Error
Keywords:      Classic
User:          SYSTEM
Computer:      PKI01.abc.corp
Description:
Active Directory Certificate Services could not use the default provider for encryption keys.  Keyset does not exist 0x80090016 (-2146893802)

When I searched for this error, I found out that it is regarding key archival and recovery. But I have not configured key recovery on my CA. I have configured "Do not archive the key" under Recovery Agents on the CA Properties.  

Is there any other reason to keep getting this error? 

Thank you.