jsonp not finding my function

Question

I created an asp.net aspx page. My aspx html side is empty and the codebehind is:

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  Response.ContentType = "application/x-javascript"
  Response.Write("jsonFlickrFeed({""items"": [{""tags"": ""portrait""}] })")
  Response.End
End Sub

My json query looks like this:

$.getJSON("MyUrlOnAnotherDomain.com?jsoncallback=?", jsonFlickrFeed);
function jsonFlickrFeed(data)
{
  debugger;
}

Now everytime I try to run this I get the error: jsonFlickrFeed is undefined. When I replace the url to flicker, then it works fine. I also tried to set the contentType to JSON, but that does not change anything either. Whats wrong here?