Press the Motion Sensor Set button for 5 seconds. The Motion Sesor LED will be blinking brightly for the next 4 minutes. Press the Set button on the EZSrve until the LED stops flashing on the Motion Sensor. This took less than 5 seconds on a test I ran before doing this post. If the Motion Sensor LED does not go out then plug one of the Access Points into the same circuit as the EZSrve (for test purposes only) and repeat the link test. It sounds like the Motion Sensor and Access Point are not close enough to each other or the EZSrve and Access Point are not close enough to each other.
EDIT; I would suggest updating EZSrve through the Java Discovery tool to 02.06.12. It is labeled a Beta but has been around for several months and has some fixes for problems in 02.06.