jQuery('#img_dialog').load("~/EquipTrak/GetEquipImages", {}, function(responseText, textStatus, XMLHttpRequest) {
                  // XMLHttpRequest.responseText has the error info you want.
                  alert(XMLHttpRequest.responseText);
              });

              jQuery('#img_dialog').dialog('open');
              return false;
          },

   <div id="img_dialog" title="Images for <%= ViewData["EquipID"] %>">
    <% using (Html.BeginForm("Upload", "File", FormMethod.Post, new { enctype = "multipart/form-data" }))
       {%>
        <p><input type="file" id="fileUpload" name="fileUpload" size="23"/> </p>
        <p><input type="submit" value="Upload file" /></p>
        <p></p>
        <center>
        <ul style="list-style-type:none">
        <li><%= ViewData["ImagePath"]%></li>
        </ul>
        </center>

    <% } %>
</div>

ViewData["EquipID"] = strEquipID;

        ViewData["ImagePath"] = "/Content/equip_images/sub_hoe1.jpg";

return View();
    }