Please put code in <c>...</c> tags.

Check your error log when you get 500 error. You should see:

Service description 'http://www.xmethods.net/sd/StockQuoteService.wsdl
+' can't be loaded: 404 Not Found
[download]

That URL is no longer valid.

( Even that did work, you're also not emitting a necessary CGI header like jhourcle points out! )