Hi Duriez
I'm not with Laminar Research, just a fellow simmer in the UK, but initially the best thing to do is to re-run the X-Plane 11 Installer application, as this will scan your existing files to see if any are missing, corrupt or in need of updating.
If this doesn't work for some reason and assuming that you are running a valid copy of X-Plane 11 purchased directly from LR, then I would be happy to send you a copy of the relevant file by email if you wish?
Regards