diff --git a/tools/ecmaTester.js b/tools/ecmaTester.js
index 22a79aac..fa753fcf 100644
--- a/tools/ecmaTester.js
+++ b/tools/ecmaTester.js
@@ -4,6 +4,9 @@
 // It is expected to minify and execute the script without problems
 // as a failed test is indicated by throwing an exception.
 
+// How to use (assuming the current working directory is a checkout of the test262 repo):
+// [path to python2 executable] .\tools\packaging\test262.py --command "node <pathTo>\UglifyJS2\tools\ecmaTester.js" [add some words as filter (like 'language')]
+
 // argv number 2 is assumed to be the input file
 var file = process.argv[2];
 
@@ -11,41 +14,63 @@ var fs = require("fs");
 var vm = require("vm");
 var UglifyJS = require("./node.js");
 
-console.log("Using node " + process.versions.node);
-console.log(process.versions);
+console.log("Using ", process.versions);
+
+var minified = "[Nothing]";
+var source;
+var issues = false;
+var unminifiedError = "";
+var sameError = false;
 
-var result = "[Nothing]";
 try {
     // Compress file
-    result = UglifyJS.minify(file).code;
-    // Run result to make sure the script is still runable
-    vm.runInNewContext(result, {});
+    minified = UglifyJS.minify(file).code;
+    // Run the minified code to check if the script is still runable
+    vm.runInNewContext(minified, {});
 
 } catch(e) {
-    // Report
-    console.log("A minified script failed to run");
-    console.log("file: " + file);
-    console.log("minified output:");
-    console.log(result);
-    console.log();
-    console.log("==========");
-    console.log(e);
-    console.log(e.stack);
-    console.log();
-    console.log("Now running script without minification...");
-    console.log();
-
     // Make sure script runs fine without compiling as well
-    input = fs.readFileSync(file, {encoding: 'utf8'});
-    try {
-        vm.runInNewContext(input, {});
-        console.log("Ran without problems unminified");
-    } catch (e2) {
-        console.log("Failed to run script unminified as well");
-        console.log(e2.stack);
+    source = fs.readFileSync(file, {encoding: 'utf8'});
+    issues = true;
 
-        process.exit(2); // Nope...
+    // Investigate if an error occurs unminified as well
+    try {
+        vm.runInNewContext(source, {});
+        issues = false;
+        unminifiedError += "Ran unminified without problems";
+
+    } catch (e2) {
+        unminifiedError = "Error while running the unminified version:\n";
+        unminifiedError += "Error: " + e2 + "\n";
+        unminifiedError += "Stack: " + e2.stack;
+        if (e2 + "" == e + "") {
+            sameError = true;
+        }
     }
 
-    process.exit(1); // We found a great mystery to solve
+    // Report
+    console.log("A minified script failed to run " +
+        (issues ?
+            "both minified and minified. This is likely an invalid js file" +
+            " or has code the interpreter engine doesn't understand." :
+            "after being minified. Please report node version, test" +
+            " and error to the maintainer of the minifier tool."
+        )
+    );
+    console.log("Version: Node " + process.versions.node);
+    console.log("File (may be a temp file): " + file);
+    console.log("Error: ", e);
+    console.log("Stack: ", e.stack);
+    console.log("\n\n");
+    console.log(unminifiedError);
+    console.log();
+    if (!sameError) {
+        console.log("Minified output:");
+        console.log(minified);
+        console.log();
+    }
+    console.log("==========\n");
+
+    // Exit 1 if its our fault, exit 2 if the interpreter fails as well
+    process.exit(issues ? 2 : 1);
 }
\ No newline at end of file