not able call 'Saveas' function to save pdf as word through acrobat. throws reflection exception.

I am trying to convert a pdf  to word and save it programitcally through api. I have tried the sample  given in the sdk in the C# samples folder by changing the code from other refrences. However i am getting reflection error as ' Target type doesn't match' . Here is my code

AcroPDDoc pdfd = new AcroPDDoc();

                pdfd.Open(filename);

                Object jsObj = pdfd.GetJSObject();

                Type jsType = pdfd.GetType();

                //have to use acrobat javascript api because, acrobat

                object[] saveAsParam = { "newFile.docx", "com.adobe.acrobat.docx", "", false, false };

                jsType.InvokeMember("saveAs", BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Instance, null, jsObj, saveAsParam, CultureInfo.InvariantCulture);

A dialog box is opened and file to convert will be chosen. As of i know this is a working code for many.What am i doing wrong .Please help.I have Acrobat DC installed on my system.This is my version