Difficulty Building XML-RPC.NET Client (To use with Moodle)

I am using the CookComputing XML-RPC Library in an attempt to build a C# console client in order to execute API methods on Moodle (an open-source Learning management system). The server is using ZEND XML-RPC. **When I run the code, I get a TypeLoadException was Unhandled**, referring to this line: System.Object myResults = proxy.moodle_user_get_user_by_id(myUserIds); *"Inheritance security rules violated while overriding member: 'CookComputing.XmlRpc.XmlRpcFaultException.GetObjectData(System.Runtime.Serialization.SerializationInfo, System.Runtime.Serialization.StreamingContext)'. Security accessibility of the overriding method must match the security accessibility of the method being overriden."* **My Client code is:** ... using CookComputing.XmlRpc; [XmlRpcUrl("http://moodle.ourcompany.com/webservice/xmlrpc/server.php?wstoken=somereallylongtokenstring")] public interface IMoodleUserGetUsersById : IXmlRpcProxy { [XmlRpcMethod("moodle_user_get_users_by_id")] System.Object moodle_user_get_user_by_id(int[] userIds); } namespace Moodle_test_api1 { class Program { static void Main(string[] args) { Console.WriteLine("Testing XML-RPC Services for Moodle!"); IMoodleUserGetUsersById proxy = XmlRpcProxyGen.Create<IMoodleUserGetUsersById>(); int[] myUserIds = {11, 12}; System.Object myResults = proxy.moodle_user_get_user_by_id(myUserIds); //Console.WriteLine("Trying Function: {0}:{1}", proxy.ToString()); } } } ---- **The API documentation for the method I want to utilize is:** moodle_user_get_users_by_id: Get users by id. Arguments --------- userids (Required) General structure list of ( int //user ID ) XML-RPC (PHP structure) [userids] => Array ( [0] => int ) Response: General structure ----------------- list of ( object { id double //ID of the user username string //Username policy is defined in Moodle security config firstname string //The first name(s) of the user lastname string //The family name of the user email string //An email address - allow email as root@localhost auth string //Auth plugins include manual, ldap, imap, etc confirmed double //Active user: 1 if confirmed, 0 otherwise idnumber string //An arbitrary ID code number perhaps from the institution lang string //Language code such as "en", must exist on server theme string //Theme name such as "standard", must exist on server timezone string //Timezone code such as Australia/Perth, or 99 for default mailformat int //Mail format code is...