diff --git a/lib/post.js b/lib/post.js
index 449c96c..421bd00 100644
--- a/lib/post.js
+++ b/lib/post.js
@@ -8,6 +8,7 @@ var xpi = require("./xpi");
 var fs = require("fs");
 var url = require("url");
 var net = require("net");
+var when = require("when");
 
 function postXPI (manifest, options) {
   var postURL = options.postUrl;