Hi Joseph,
Welcome.
Lets start afresh.
Please disable any Antivirus and firewall.
Please use Windows to uninstall FMS Data Manager. Specifically use FAQ - Charts desktop installer fails immediately
If they exist, please delete folders:
c:\ProgramData\Navigraph\FMSClient and c:\Program Files (x86)\Navigraph\FMS Data Manager.
Please download and install latest FMS Data Manager .
If still an issue, please post screenshots of Settings tab showing P3D v5 path and Addon Mappings tab showing PMDG paths. If still no joy you may need to add PMDG manually there.
Please let us know how you get on.
Cheers
Ian