Silverlight WebRequest fails with "The URI prefix is not recognized"

I have a silverlight library that is supposed to get make a web service request and receive an xml response:

   Uri uri = new Uri("http://some_server:51306/getStuff.xml?id=14");            
   WebRequest request = WebRequest.Create(uri);

However, WebRequest.Create(uri) fails with the exception "The URI prefix is not recognized".

Note that I am running the program using a unit test from a non-silverli开发者_开发百科ght dll. I need to build a test suite for the app!

Any ideeas?

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Try setting the .Web project as the default startup project instead of the Silverlight project

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Have you tried adding the second parameter to the Uri constructor?

 Uri uri = new Uri("http://some_server:51306/getStuff.xml?id=14", UriKind.Absolute);