diff -r 4b65abc39565 -r 5b3ae17babdf launcher/http/src/main/java/org/apidesign/bck2brwsr/launcher/Bck2BrwsrLauncher.java
--- a/launcher/http/src/main/java/org/apidesign/bck2brwsr/launcher/Bck2BrwsrLauncher.java	Thu May 09 21:51:56 2013 +0200
+++ b/launcher/http/src/main/java/org/apidesign/bck2brwsr/launcher/Bck2BrwsrLauncher.java	Mon Sep 23 00:59:14 2013 +0200
@@ -51,9 +51,13 @@
               "(function WrapperVM(global) {"
             + "  function ldCls(res) {\n"
             + "    var request = new XMLHttpRequest();\n"
+            + "    console.log('Loading ' + res);\n"
             + "    request.open('GET', '/classes/' + res, false);\n"
             + "    request.send();\n"
-            + "    if (request.status !== 200) return null;\n"
+            + "    if (request.status !== 200) {\n"
+            + "      console.warn('  cannot load ' + res);\n"
+            + "      return null;\n"
+            + "    }\n"
             + "    var arr = eval('(' + request.responseText + ')');\n"
             + "    return arr;\n"
             + "  }\n"