The LEDs are documented on page 6 of the Quick Start Guide (http://www.cisco.com/c/dam/en/us/td/docs/wireless/access_point/csbap/wap371/quick_guide/guide/QSG_ENGLISH.pdf), but the states you describe don't indicate anything unusual. So a couple of questions:
1. Do you know if the WAP is actually operating - has clients associated with it?
2. If you connect to one of the other WAPs, do you see this one listed in the access point table under single point setup?
3. If it is listed in the access point table, can you connect to the web UI of the problem WAP using the IP address shown in the table?
4. What firmware version is the cluster running?
What I am trying to figure out is whether the WAP is completely offline, or if there is a problem with Bonjour, which is what FindIT uses to discover the device.
I'd also suggest moving this thread to the wireless forum, as that's where you will find the wireless specialists.