diff -r ba912ef24b27 -r 7f11e94f413d launcher/http/src/main/java/org/apidesign/bck2brwsr/launcher/CompileCP.java
--- a/launcher/http/src/main/java/org/apidesign/bck2brwsr/launcher/CompileCP.java	Wed Apr 30 15:04:10 2014 +0200
+++ b/launcher/http/src/main/java/org/apidesign/bck2brwsr/launcher/CompileCP.java	Fri May 02 09:06:18 2014 +0200
@@ -93,7 +93,11 @@
                     .resources(new EmulationResources() {
                         @Override
                         public InputStream get(String resource) throws IOException {
-                            return r != null ? r.get(resource, 0).openStream() : super.get(resource);
+                            if (r != null) {
+                                final URL url = r.get(resource, 0);
+                                return url == null ? null : url.openStream();
+                            }
+                            return super.get(resource);
                         }
                     })
                     .generate(w);