diff --git a/common/content/services.js b/common/content/services.js
index ad056221..29a76e80 100644
--- a/common/content/services.js
+++ b/common/content/services.js
@@ -47,6 +47,7 @@ const Services = Module("services", {
         this.addClass("file:",      "@mozilla.org/network/protocol;1?name=file", Ci.nsIFileProtocolHandler);
         this.addClass("find",       "@mozilla.org/embedcomp/rangefind;1",        Ci.nsIFind);
         this.addClass("process",    "@mozilla.org/process/util;1",               Ci.nsIProcess);
+        this.addClass("zipWriter",  "@mozilla.org/zipwriter;1",                  Ci.nsIZipWriter);
 
         if (!this.get("extensionManager"))
             Components.utils.import("resource://gre/modules/AddonManager.jsm", modules);