diff --git a/lib/API/Modules/Modularizer.js b/lib/API/Modules/Modularizer.js
index 73cdf558..5b795259 100644
--- a/lib/API/Modules/Modularizer.js
+++ b/lib/API/Modules/Modularizer.js
@@ -169,15 +169,15 @@ function installModule(CLI, module_name, opts, cb) {
         Common.printError(e);
       }
 
-      Common.extend(opts, {
+      opts = Common.extend(opts, {
         cmd : cmd,
         development_mode : development_mode,
         proc_path : proc_path
       });
 
       Configuration.set(MODULE_CONF_PREFIX + ':' + canonic_module_name, {
-        uid : opts.uid || null,
-        gid : opts.gid || null
+        uid : opts.uid,
+        gid : opts.gid
       }, function(err, data) {
 
         startModule(CLI, opts, function(err, dt) {
diff --git a/lib/Common.js b/lib/Common.js
index 62aeab44..7f43e07b 100644
--- a/lib/Common.js
+++ b/lib/Common.js
@@ -445,8 +445,13 @@ Common.printOut = function() {
 /**
  * Raw extend
  */
-Common.extend = function(destination, source){
-  if (!source || typeof source != 'object') return destination;
+Common.extend = function(destination, source) {
+  if (typeof destination !== 'object') {
+    destination = {};
+  }
+  if (!source || typeof source !== 'object') {
+    return destination;
+  }
 
   Object.keys(source).forEach(function(new_key) {
     if (source[new_key] != '[object Object]')