diff --git a/src/import/sb2import.js b/src/import/sb2import.js
index ea22398a4..3b1ef0373 100644
--- a/src/import/sb2import.js
+++ b/src/import/sb2import.js
@@ -158,7 +158,7 @@ var parseScratchObject = function (object, runtime, topLevel) {
  * @property {number} rotationCenterY - the Y component of the costume's origin.
  * @property {number} [bitmapResolution] - the resolution scale for a bitmap costume.
  * @param {!Runtime} runtime - Scratch runtime, used to access the storage module.
- * @returns {Promise} - a promise which will resolve after skinId is set, or null on error.
+ * @returns {?Promise} - a promise which will resolve after skinId is set, or null on error.
  */
 var loadCostume = function (md5ext, costume, runtime) {
     if (!runtime.storage) {
diff --git a/src/virtual-machine.js b/src/virtual-machine.js
index 498f1bfbf..9c6ee0b54 100644
--- a/src/virtual-machine.js
+++ b/src/virtual-machine.js
@@ -2,6 +2,7 @@ var EventEmitter = require('events');
 var util = require('util');
 
 var filterToolbox = require('./util/filter-toolbox');
+var log = require('./util/log');
 var Runtime = require('./engine/runtime');
 var ScratchStorage = require('scratch-storage');
 var sb2import = require('./import/sb2import');