Certificate Renewal Issue

Hi,  We have a Microsoft 2008 R2 server. When attempting to renew a certificate we are getting exception "Provider could not perform the action since the context was acquired as silent. 0x80090022".  We want to renew the certificate with the same existing key pair.

We are trying to achieve this programmatically using c# and getting exception at 

objPkcs7.InitializeFromCertificate(X509CertificateEnrollmentContext.ContextUser, true, Convert.ToBase64String(certificate.RawData), EncodingType.XCN_CRYPT_STRING_BASE64, X509RequestInheritOptions.InheritPrivateKey);

Any ideas/suggestions where we are going wrong and what this error means??