diff --git a/lib/coffee-script/coffee-script.js b/lib/coffee-script/coffee-script.js
index 4c548b99..12c434ab 100644
--- a/lib/coffee-script/coffee-script.js
+++ b/lib/coffee-script/coffee-script.js
@@ -1,6 +1,6 @@
 // Generated by CoffeeScript 1.7.1
 (function() {
-  var Lexer, SourceMap, compile, formatSourcePosition, fs, getSourceMap, helpers, lexer, parser, path, sourceMaps, vm, withPrettyErrors,
+  var Lexer, SourceMap, compile, ext, formatSourcePosition, fs, getSourceMap, helpers, lexer, parser, path, sourceMaps, vm, withPrettyErrors, _i, _len, _ref,
     __hasProp = {}.hasOwnProperty,
     __indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
 
@@ -186,6 +186,18 @@
     return require('./register');
   };
 
+  if (require.extensions) {
+    _ref = this.FILE_EXTENSIONS;
+    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
+      ext = _ref[_i];
+      if (require.extensions[ext] == null) {
+        require.extensions[ext] = function() {
+          throw new Error('Use CoffeeScript.register() or the coffee-script/register module to dynamically load CoffeeScript files');
+        };
+      }
+    }
+  }
+
   exports._compileFile = function(filename, sourceMap) {
     var answer, err, raw, stripped;
     if (sourceMap == null) {
@@ -233,9 +245,9 @@
   parser.yy = require('./nodes');
 
   parser.yy.parseError = function(message, _arg) {
-    var errorLoc, errorTag, errorText, errorToken, token, tokens, _ref;
+    var errorLoc, errorTag, errorText, errorToken, token, tokens, _ref1;
     token = _arg.token;
-    _ref = parser.lexer, errorToken = _ref.errorToken, tokens = _ref.tokens;
+    _ref1 = parser.lexer, errorToken = _ref1.errorToken, tokens = _ref1.tokens;
     errorTag = errorToken[0], errorText = errorToken[1], errorLoc = errorToken[2];
     errorText = errorToken === tokens[tokens.length - 1] ? 'end of input' : errorTag === 'INDENT' || errorTag === 'OUTDENT' ? 'indentation' : helpers.nameWhitespaceCharacter(errorText);
     return helpers.throwSyntaxError("unexpected " + errorText, errorLoc);
@@ -292,11 +304,11 @@
   sourceMaps = {};
 
   getSourceMap = function(filename) {
-    var answer, _ref;
+    var answer, _ref1;
     if (sourceMaps[filename]) {
       return sourceMaps[filename];
     }
-    if (_ref = path != null ? path.extname(filename) : void 0, __indexOf.call(exports.FILE_EXTENSIONS, _ref) < 0) {
+    if (_ref1 = path != null ? path.extname(filename) : void 0, __indexOf.call(exports.FILE_EXTENSIONS, _ref1) < 0) {
       return;
     }
     answer = exports._compileFile(filename, true);
@@ -318,10 +330,10 @@
       }
     };
     frames = (function() {
-      var _i, _len, _results;
+      var _j, _len1, _results;
       _results = [];
-      for (_i = 0, _len = stack.length; _i < _len; _i++) {
-        frame = stack[_i];
+      for (_j = 0, _len1 = stack.length; _j < _len1; _j++) {
+        frame = stack[_j];
         if (frame.getFunction() === exports.run) {
           break;
         }
diff --git a/src/coffee-script.coffee b/src/coffee-script.coffee
index 639d2b4a..68ce8569 100644
--- a/src/coffee-script.coffee
+++ b/src/coffee-script.coffee
@@ -158,6 +158,14 @@ exports.eval = (code, options = {}) ->
 
 exports.register = -> require './register'
 
+# Throw Error to register extension explicitly.
+if require.extensions
+  for ext in @FILE_EXTENSIONS
+    unless require.extensions[ext]?
+      require.extensions[ext] = ->
+        throw new Error('''Use CoffeeScript.register() or the coffee-script/register module \
+          to dynamically load CoffeeScript files''')
+
 exports._compileFile = (filename, sourceMap = no) ->
   raw = fs.readFileSync filename, 'utf8'
   stripped = if raw.charCodeAt(0) is 0xFEFF then raw.substring 1 else raw