Whenever a co-worker of mine sends a message to me via MSN Messenger,
immediately following his message is the following:

@[fwpscript]Version:01.03.01.05|Icon:none|rsvp@[/fwpscript]

His screen does not show this as being sent, and I only get this from him.
Any idea what this is? A virus scan shows his system as being clean.