I regret for the long delay in getting back with you. ActiveX control '8856f961-340a-11d0-a96b-00c04fd705a2' cannot be instantiated because the current thread is not in a single-threaded apartment.
We can able to resolve the above reported issue by adding the AspCompact="true" attribute to the page directive in Default.aspx file.
Kindly refer the below code snippet which helps to resolves the above reported issue.
<%@ Page Language="C#" AutoEventWireup="true" AspCompat ="true" CodeFile="Default.aspx.cs" Inherits="Default" %>
Please do find the sample from the below specified location which resolves the above reported issue and let us know if this helps.http://files.syncfusion.com/support/pdf.Web/F90473/Sample.zip