I've been reading an article on LR's website about this XPLM file and apparently it is what X-Plane 11 uses to manage all other functioning plugins that exist on someone's PC.
The problem may not therefore actually be do to with the XPLM plugin itself, but any of the others that you may have in your C:\X-Plane 11\Resources\plugins folder.
Consequently, I can only suggest the following steps:-
1. Run the X-Plane Installer program again, just in case a file has become corrupt or is missing
2. Go into your C:\X-Plane 11\Resources\plugins folder and remove one plugin at a time and restart X-Plane 11 to see if it makes any difference. If you do this, please copy & paste each of the plugins to a temporary folder and somewhere safe first, so that you can copy it back again afterwards if you need to.
Not sure if I can be any more help, but if you need assistance moving plugins about, please let me know?