COMException was unhandled by user code(Exception from HRESULT: 0xC00CE508) win8 metro apps

I'm writing a little application on WinRT Metro Apps. I need to read an xml file and i get a awful COMException :/

This is which should read this xml:

Windows.Storage.StorageFolder storageFolder = await
   Windows.ApplicationModel.Package.Current.InstalledLocation
   .GetFolderAsync("Common");

Windows.Storage.StorageFile storageFile = await
   storageFolder.GetFileAsync("testFile.xml");

var stream = await storageFile.OpenAsync(Windows.Storage.FileAccessMode.Read);

XmlDocument doc = await XmlDocument.LoadFromAsync(storageFile);

Can somebody give me somes tips to make it work?

Why do you use OpenAsync()? (Further more, doesn't the method named LoadFromAsync exist?) Please see this Web page: How to read and write data into XML file In Metro style apps ?

By the way, error 0xC00CE508 occurs in many cases, while parsing XML. Please check that the contents of the XML have no error, by using the XmlDocument.LoadXml(String) method.