Hey Hervé,
What version do you have of both of the following items:
• The Events Calendar
• Events Calendar PRO
If they’re not 3.10.1, please update both versions to that.
Also, it seems you’ve changed the folder name of the plugin, by changing it to TEC-PRO. Why did you do this, and if you revert it to the original name (which you can see if you go to http://theeventscalendar.com/my-account/downloads and download a copy of the plugin), does anything improve? I know that seems like a minor detail, but just not sure why this error would appear on your site but nowhere else.
Thanks!
George