fix loading pty.js in local version

node_modules/c9/setup_paths.js

@@ -13,9 +13,11 @@ modules._resolveFilename = function(request, parent) {
     // Ensure client extensions can be loaded
     request = request.replace(/^lib\//, "node_modules/");
     // ensure we never use node_modules outside of root dir
-    parent.paths = parent.paths.filter(function(p) {
-        return p.indexOf(root) == 0
-    });
+    if (parent.paths[0] && parent.paths[0].indexOf(root) == 0) {
+        parent.paths = parent.paths.filter(function(p) {
+            return p.indexOf(root) == 0;
+        });
+    }
     // Add the extra paths
     extraPaths.forEach(function(p) {
         if (parent.paths.indexOf(p) === -1)