I have a strange problem with a WebRequest. It used to work just fine, but now I get an exception (Invalid URI: The hostname could not be parsed.) every time I try to get the response from that request.

Stack Trace:

Code:
   at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
   at System.Uri..ctor(String uriString)
   at System.Net.WebProxy.CreateProxyUri(String Address)
   at System.Net.WebProxy..ctor(String
...