The PMS on QNAP NAS (I don't know for any of the other NAS) is located in a /.qpkg/PlexMediaServer/ folder. It is a linux based system.
So the Settings in your index.php need more flexibility to consider this kind of path and like I said I don't even know what the other NAS use as path... Plus accessing the linux System through a php file when the qpkg folder is not supposed to be openly accessible in the first place might be tricky... You have to put the PlexUSM folder in a web folder on the nas then launch the index.php from there which is easy enough but then go up a folder and then find the .qpkg folder and so on. Seems relatively straightforward but linux is so weird... I have no idea what it might do.
I'd say :
$PathToPlexMediaFolder = "../.qpkg/PlexMediaServer/Library/Plex Media Server/Media/localhost"
and
$PathToPlexDatabase = "../.qpkg/PlexMediaServer/Library/Plug-in Support/Databases/com.plexapp.plugins.library.db"
should be working on a QNAP... I didn't look though if you just using this would do the job. You migh have some reference on other files to windows path or something?
Anyway those give me a blank page just as with windows settings so it is not that. I am clueless with Linux anyway.
PlexExport uses a totally different approach to gather metadata from PMS, on whatever plateform you are. So maybe there are idea to gather from their "cli.php" file.
