Having Trouble setting up MVC3 application with DPM

[MDL801]

Hello All I have been lurking this site for days and have done endless google searches to try to get this problem that I am having taken care of and anyhelp would be greatly appreciated.

I have a MVC3 application with Razor syntax and am having issues getting the 15 minute test to work...the error that I am getting is:

An error occurred while trying to report this transaction to the merchant. An e-mail has been sent to the merchant informing them of the error. The following is the result of the attempt to charge your credit card.

This transaction cannot be accepted.

A few of the post that I have read state that Authorize.net is working on updating the documentation to fit C# 4.0 syntax an I am wondering if anyone has working test code that will work for me? Or is able to guide me in the right direction.

[Trevor]

The error that you are receiving is not necessarily related to the SDK that you are using.  This error indicates that Authorize.Net is unable to load your relay response page that is used as a part of the DPM process.  The most common cause of this error during development is the use of an internal server that is not publicly accessible.  In order to avoid this error, your testing environment must be publicly accessible.