I have two servers in a web farm that are (as far as I can tell) configured
exactly the same.  One server works fine when runnin the following code, the
other throws an exception.  The code and execption are:

HttpWebRequest request;
request =
(HttpWebRequest)WebRequest.Create(@"https://wwwcie.ups.com/ups.app/xml/Track");
HttpWebResponse response;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = authXml.Length + requestXml.Length;
StreamWriter requestString = new StreamWriter(request.GetRequestStream());
requestString.Write(authXml + requestXml);
requestString.Close();
request.Timeout = 15000;
response = (HttpWebResponse)request.GetResponse();
using (StreamReader sr = new StreamReader(response.GetResponseStream()))
{
    return sr.ReadToEnd();
}

EXCEPTION:

System.Net.WebException: The underlying connection was closed: Could not
establish secure channel for SSL/TLS. --->
System.TypeInitializationException: The type initializer for
"System.Net.SecureChannel" threw an exception. --->
System.EntryPointNotFoundException: Unable to find an entry point named
EnumerateSecurityPackagesW in DLL security.dll. at
System.Net.NativeNTSSPI.EnumerateSecurityPackagesW(Int32& pkgnum, IntPtr&
arrayptr) at
System.Net.SSPISecureChannelType.EnumerateSecurityPackages(Int32& pkgnum,
IntPtr& arrayptr) at
System.Net.SSPIWrapper.EnumerateSecurityPackages(SSPIInterface SecModule) at
System.Net.SSPIWrapper.GetSupportedSecurityPackages(SSPIInterface SecModule)
at System.Net.SecureChannel..cctor() --- End of inner exception stack trace
--- at System.Net.SecureChannel..ctor(String hostname,
X509CertificateCollection clientCertificates) at
System.Net.TlsStream.Handshake(ProtocolToken message) --- End of inner
exception stack trace --- at System.Net.HttpWebRequest.CheckFinalStatus() at
System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult) at
System.Net.HttpWebRequest.GetRequestStream() at
NSP.Utilities.UPS.processUPSRequest(String requestXml, UPSRequestType type)

Any ideas?