Opening Outlook with attachment

[Guest]

Hi all,
I am trying to open outlook express along with an attachment.
I have added a reference to the Microsoft outlook Library
I am using the following lines of code.
=============================
Outlook.Application OutApp = new Outlook.Application();
Outlook.OlItemType olItem = new Outlook.OlItemType();
Outlook.MailItem OutMail = (Outlook.MailItem)OutApp.CreateItem(olItem);
OutMail.To = ToAddress;
//OutMail.SenderName = FromAddress;
OutMail.Subject= Subject;
//OutMail.Attachments.Add(Filename,);
OutMail.Body = Body;
OutMail.Display(OutApp);
=============================

While compiling it doesnt give any error. However when I run the code it fails at the first line where I am trying to create an object of Outlook Application type
The error says " Acess is denied"

When I try to open outlook using mailto: it opens fine, but I am not able to attach a file to it at the runtime.
Any help on this will be highly appreciated.