var
fac: IWebClassFactory;
pkey: IX509PrivateKey;
CertificateRequestPkcs10: IX509CertificateRequestPkcs10;
DistinguishedName: IX500DistinguishedName;
KeyUsageExtension: IX509ExtensionKeyUsage;
Enroll: IX509Enrollment;
certReq: WideString;
begin
try
CoInitializeEx(nil, 2);

fac := CoWebClassFactory.Create;

pkey := fac.CreateObject('X509Enrollment.CX509PrivateKey') as IX509PrivateKey;

pKey.ProviderName := 'Crypto-Pro GOST R 34.10-2001';
pKey.ProviderType := 75;
pKey.KeySpec := XCN_AT_KEYEXCHANGE;
pkey.Existing := false;
pkey.ContainerName := 'a';
//pkey.ContainerNamePrefix := 'abc';
pkey.KeyProtection := XCN_NCRYPT_UI_NO_PROTECTION_FLAG;
pkey.ExportPolicy := XCN_NCRYPT_ALLOW_EXPORT_FLAG;
pkey.Length := 256;

CertificateRequestPkcs10 := fac.CreateObject(
'X509Enrollment.CX509CertificateRequestPkcs10') as IX509CertificateRequestPkcs10;
CertificateRequestPkcs10.InitializeFromPrivateKey(ContextUser, PKey, '');

DistinguishedName := fac.CreateObject(
'X509Enrollment.CX500DistinguishedName') as IX500DistinguishedName;
DistinguishedName.Encode('CN="TestName"', 0);
CertificateRequestPkcs10.Subject := DistinguishedName;

KeyUsageExtension := fac.CreateObject(
'X509Enrollment.CX509ExtensionKeyUsage') as IX509ExtensionKeyUsage;
KeyUsageExtension.InitializeEncode(
CERT_KEY_ENCIPHERMENT_KEY_USAGE OR
CERT_DATA_ENCIPHERMENT_KEY_USAGE OR
CERT_DIGITAL_SIGNATURE_KEY_USAGE OR
CERT_NON_REPUDIATION_KEY_USAGE
);
CertificateRequestPkcs10.X509Extensions.Add(KeyUsageExtension);

Enroll := fac.CreateObject('X509Enrollment.CX509Enrollment') as IX509Enrollment;
Enroll.InitializeFromRequest(CertificateRequestPkcs10);

---> здесь происходит ошибка.
certReq := Enroll.CreateRequest(XCN_CRYPT_STRING_BASE64HEADER);
writeln(certReq);

writeln('OK');
sleep(1000);
except
on E: Exception do begin
writeln('Error: ' + e.message);
writeln('Press ENTER to continue...');
readln;
writeln;
end;
end;