What have you done, tried or considered already?
What is the notification you get? The actual words and the nature/type of message.
First hit Google: "avp.exe is a process belonging to Kaspersky Internet Security Suite..."
I'd bet the fire wall has detected a change in Apache and keeps asking you to confirm that is ok for it to connect with a port. I bet there's a box to tick when you answer "yes" to remember/repeat that in the future, so you won't be asked again, until Apache changes again.
Not XAMPP me thinks.