If the Plug-ins-xxxxxxx folder is not moved to the C:\Program Files\Plex\Plex Media Server\Resources folder by the installer then there won’t be any bundles for the PlexScriptHost.exe to run and I would suspect that is why they do not show in Task Manager.
An uninstall and re-install may fix the problem if there is not something that is blocking moving folders - eg some live backup software or some anti-virus software may lockdown a folder whilst it is performing its task making any move action to fail with a windows share violation.
To identify what is causing the move folder to fail, one would need to have ProcMon running capturing events before the install sequence is initiated - if the problem arises then the saved procmon PML file together with the installer logs (which are initially in %TEMP%) would identify the reason.
Note that PML files are very large but they do zip very well. The zip would need tp be uploaded externally and a link provided.
FYI this is the forum topic where we had a failure on the move folder (we use windows rename system call to do that)
