Not able to access the sharepoint site from an external machine

Question

I created a list in a sharepoint site (2007). I was trying to access that list from another machine in which WSS is installed. But I am getting the following error.

  The Web application at http://mysite.com/Test/ could not be found. Verify that you have typed the URL correctly. If the URL should be serving existing content, the system administrator may need to add a new request URL mapping to the intended application

I used the following code

using (SPSite siteCollection = new SPSite("http://mysite.com/Test/"))
        {

            SPWeb web = siteCollection.OpenWeb();
            SPList list = web.Lists["ListName"];
            SPListItem oListItem = list.Items.GetItemById(Convert.ToInt32("1"));
            lblDocumentName.Text = oListItem["Name"].ToString();

        }

Any suggessions, why is error occurs