"This feature requires you to be using a Microsoft Exchange Server e-mail account. The recipient of the mail you want to recall must also be using an Exchange server e-mail account."
So the first step would be to contact the administrator of the MS Exchange Server that hosts your e-mail account. If he can't help, the next person to sort this out would be the administrator of your PC. This assumes this is a business PC. Most private PC's aren't connected to MS Exchange, after all.
Hope this helps.