diff --git a/lib/extension-wrapper.coffee b/lib/extension-wrapper.coffee
index ac22510..29cd095 100644
--- a/lib/extension-wrapper.coffee
+++ b/lib/extension-wrapper.coffee
@@ -20,7 +20,7 @@ script = require("#{process.argv[2]}/#{process.argv[3]}")
 
 
 process.on('message', (message) ->
-  script[message[1]](message.slice(2), (err, res) ->
+  script[message[1][0]](message[1].slice(1), (err, res) ->
     throw err if err
     process.send([message[0], res])
   )
diff --git a/lib/extensions.coffee b/lib/extensions.coffee
index 8520f94..12db54d 100644
--- a/lib/extensions.coffee
+++ b/lib/extensions.coffee
@@ -36,7 +36,7 @@ messageHandler = (message) ->
 run = (args, callback) ->
   scriptName = args[0]
   if not processes[scriptName]?
-    cwd = path.resolve(config.get('CONFIG_DIR'), 'extensions')
+    cwd = path.resolve(config.get('CONFIG_DIR'), 'ext')
     p = childProcess.fork('lib/extension-wrapper', [cwd, scriptName])
     p.on('message', messageHandler)
     processes[scriptName] = p
diff --git a/lib/sandbox.coffee b/lib/sandbox.coffee
index c2ecf63..43414a0 100644
--- a/lib/sandbox.coffee
+++ b/lib/sandbox.coffee
@@ -54,7 +54,7 @@ Object.defineProperty(sandbox.context, 'ext', {value: () ->
 
   extCall = (String(a) for a in arguments)
   key = JSON.stringify(extCall)
-  if not sandbox.extensionsCache[sandbox.revision]?[key]?
+  if not sandbox.extensionsCache[sandbox.revision]? or key not of sandbox.extensionsCache[sandbox.revision]
     sandbox.extensions = [extCall]
     throw new Exit()