Thanks for your help.
I will ask it Sketchup.
I am very happy with the plugins from Fredo6 and they give always plain satisfaction.

TIG,

Bad news, the error message is always there after doing:

I erase Sketchup from my computer, folders, projects and plugins,
I erase Sketchup also from my downloads,
I redownload Sketchup 2020 Pro from my Sketchup account,
I reinstall Sketchup 2020 Pro via the context-menu as Administrator,
It goes very well and without any problems,
After launching the error message appear on the first page.

Error Loading File C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/su_advancedcameratools/actloader.rbe
Failed to read RBE/RBS file.
Error Loading File C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/su_dynamiccomponents/ruby/dcloader.rbe
Failed to read RBE/RBS file.
Error Loading File C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/su_sandbox/sandboxmenus.rbe
Failed to read RBE/RBS file.
Error Loading File C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/su_trimble_connect/boot.rbe
Failed to read RBE/RBS file.

As you can see I erased all plugins from Fredo6 without succes.

@unknownuser said:

Very strange, because you get the infamous message "Failed to read RBE/RBS file.", which usually comes from a permissions problem arising from the incorrect installation of Sketchup itself (you must Run the installer's exe as Administrator).

Did you try to reinstall Sketchup?

I reinstall Sketchup 2020 pro again and also Fredo6 Lib with the same result.

Fredo6 plugins don't work anymore.
Have a error message on the front page bij starting Sketchup 2020 on Window 10 pro since I load LibFredo6 - v10.1a.
No plugin are available anymore. I have downloading Sketchup 2020 and the Fredo6 plugin again with the same error message as shown below.
I ask for help, thanks.

Error Loading File C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/Fredo6_!LibFredo6/top_LibFredo6.rbe
Failed to read RBE/RBS file.
Error Loading File Fredo6_!LibFredo6.rb
Error: #<NameError: uninitialized constant LibFredo6_Loader::LibFredo6>
C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/Fredo6_!LibFredo6.rb:65:in process' C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/Fredo6_!LibFredo6.rb:72:in module:LibFredo6_Loader'
C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/Fredo6_!LibFredo6.rb:30:in <top (required)>' Error Loading File Fredo6_FredoSpline.rb Error: #<TypeError: can't convert nil into an exact number> C:/Users/Hugo/AppData/Roaming/SketchUp/SketchUp 2020/SketchUp/Plugins/Fredo6_!LibFredo6.rb:81:in -'