I’d recommend (just for the purposes of troubleshooting) these things:
Default OU blank
use your domain Administrator as the default user
then, I’d play with the domain name…
Try your FQDN (fully qualified domain name)
Try your sloppy domain name (example for My.SchoolDistrict.k12.mo.us you’d just put in “My”)
No need to change any php files. This is FOG Trunk, the days of editing PHP files are over.
The rest of your settings look good.
Now, if none of this works… keep in mind that this is client is in BETA. If you want to pursue this further, please contact @Jbob
Does your legacy client work?