The message you keep on receiving is what we called the Human Interaction Proof (HIP) challenge; it is used to reduce abuse of Windows Live Hotmail accounts. Windows Live Hotmail is a free service, and many people take advantage of that fact to create accounts to send spam, abuse, and other unwanted e-mail. Many times these people use computers to set up the accounts and to send the unwanted content. The HIP validation prevents this by displaying a puzzle that only a human can interpret and complete.
Since you are being asked to verify it every time you send out an e-mail, I need you to post your e-mail address here for me to check it out.
Note: I've moved your post to the Sending Limits forum because this is the appropriate one for it.