New Post: How to publish tweets?

its ok, I have just checked and I didn't have the right permissions on my application settings..

but, I have my colleague sending some test tweets, and I am sending a response back to him by creating a message with "@" + e.value.creator.screenname and then my message, it posts on my timeline but he doesn't seem to receive it, but saying that, he doesn't receive anything if I do it through twitter ????