1. You are using an internal ip address - does your Moodle server know how to access this? AWS is external hosting and as such, I am pretty sure you are going to need an external ip or dns.
2. Bind user can be in a different ou as long as the user has the necessary permissions on the ou that user is in.
There is a utility called ldp.exe (windows utility) that you can use to verify settings. If your moodle server is outside your network, you need to run this on a computer outside your network...