System.Net.WebPermissions exception ved læsning af xml fra web

Hej,

Jeg forsøger at læse en xml-fil fra nettet, men får smidt en SecurityException i hovdet.

Min kode:
Dim xtr As New XmlTextReader("http://site.dk/fil.xml")

Exception:
System.Security.SecurityException: Request for the permission of type System.Net.WebPermission, System, Version=1.0.5000.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 failed.
  at System.Security.CodeAccessSecurityEngine.CheckHelper(PermissionSet grantedSet, PermissionSet deniedSet, CodeAccessPermission demand, PermissionToken permToken)
  at System.Security.CodeAccessSecurityEngine.Check(PermissionToken permToken, CodeAccessPermission demand, StackCrawlMark& stackMark, Int32 checkFrames, Int32 unrestrictedOverride)
  at System.Security.CodeAccessSecurityEngine.Check(CodeAccessPermission cap, StackCrawlMark& stackMark)
  at System.Security.CodeAccessPermission.Demand()
  at System.Net.HttpRequestCreator.Create(Uri Uri)
  at System.Net.WebRequest.Create(Uri requestUri, Boolean useUriBase)
  at System.Net.WebRequest.Create(Uri requestUri)
  at System.Xml.XmlDownloadManager.GetNonFileStream(Uri uri, ICredentials credentials)
  at System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials credentials)
  at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn)
  at System.Xml.XmlTextReader.CreateScanner()
  at System.Xml.XmlTextReader.Init()
  at System.Xml.XmlTextReader.Read()
  at NewsReader.Business.XML.GetFeedItems() in H:\Applications\NewsReader\BLL\XML.vb:line 16
  at NewsReader.Form1.Form1_Load(Object sender, EventArgs e) in H:\Applications\NewsReader\Form1.vb:line 65
  at System.Windows.Forms.Form.OnLoad(EventArgs e)
  at System.Windows.Forms.Form.OnCreateControl()
  at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
  at System.Windows.Forms.Control.CreateControl()
  at System.Windows.Forms.Control.WmShowWindow(Message& m)
  at System.Windows.Forms.Control.WndProc(Message& m)
  at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
  at System.Windows.Forms.ContainerControl.WndProc(Message& m)
  at System.Windows.Forms.Form.WmShowWindow(Message& m)
  at System.Windows.Forms.Form.WndProc(Message& m)
  at System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
  at System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
  at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Hvordan løser jeg dette?

På forhånd tak.