Hi Francois, welcome to our forum!
I think the screenshot got lost, but I see you also emailed it to our support email address. I included an anonymous part of it here to benefit other readers:
What this means is that if you own a Videosync Intro license, using plugins is not supported, as detailed in our System requirements section, under Edition Compatibility.
Video playback and mixing should be fully supported though, both in Session view and if you use Live 11, also in Arrangement view.
Best,
Mattijs