Check your wireless config for anything that would block interclient communications. It's common on wifi hardware to disallow wireless devices to talk to other devices on the lan. Different brands of kit call it different things. "Wifi isolation" is the most common.
Also, "you got a wireless access point". What does that mean? Got it from where? Did you configure it yourself? Is it acting as a DHCP server? If yes, is it behind another DHCP server? Cause that'll cause you issues like this as well.