Have you tried to not use a variable in your @Path declaration? Like @Path("foo") and then hit the url : /RestSimpleApp/orders/foo. If that works, it means you have set up everything correctly, and you either cannot use a parameter in the @Path declaration or you are not doing it correctly.
I tried both URLS : /RestSimpleApp/orders/foo and URL: /RestSimpleApp/orders/foo?testid=1
for sample code, but it still gave me "The requested resource (/RestSimpleApp/orders/foo) is not available " error
I even tried to add / to Path("/foo") but it still did not work.