I followed the first way.
Finally, this is the message error.
"Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/SCF_loader.rb
(eval):352:in require': uninitialized constant SCF::SCF::TEMP Error Loading File !SketchUcation_loader.rb (eval):352:in require': uninitialized constant SCF::SCF::TEMP"

Sorry, but I don't understand your reply.
In the first capture, you can see the Plugins directoy. Inside there is a subdirectory "Sketchucation" and one file named !SketchUcation_loader.rb. Exactly what you said should be there.
What is wrong?

Yes, I followed your instructions.
I paste the images of my directories.

Thanks

I did what you said and now I get the same error message as before:
"Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/sketchUcloud.rb
uninitialized constant SUC::SCFapi
Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/SCF_loader.rb
uninitialized constant SUC::SCFapi
Error Loading File !SketchUcation_loader.rb
uninitialized constant SUC::SCFapi"

I did what you suggested but I'm sorry to say that nothing changed.
I can see some plugins in the shop, but Plugins manager, plugins extensions manager and plugins installer don't run.
Opening SU I always read the same error message:
"Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/SCF_loader.rb
(eval):353:in require': uninitialized constant SCF::SCF::TEMPError Loading File !SketchUcation_loader.rb (eval):353:in require': uninitialized constant SCF::SCF::TEMP"

I typed "SCF.constants.sort" in the Ruby Console and I got a long list of constants. Among these "SCF" and "TEMP".
Typing "SCF::TEMP" I have back: "C:/Users/HUMBERTO/AppData/Local/Temp" that is the directory where I have these files: "SketchUpHAS134H7.dmp", "SketchUpTL1L7D84.dmp"

My SCF_loader.rb has 113 lines.
Typing SCT::TEM in Ruby Console I get this msg: "Error: #<NameError: undefined local variable or method `scf' for main:Object>
(eval):304".

This is my SCF_loader.rb

Thank you TIG.
I got yours suggestions and I followed them.
Now the in the error message there isn't any longer the first line, that is:
"Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/SCF_loader.rb
(eval):352:in require': uninitialized constant SCF::SCF::TEMPError Loading File !SketchUcation_loader.rb (eval):352:in require': uninitialized constant SCF::SCF::TEMP"
I can open the shop where some plugins are listed and nothing else.

In the main page of SU I select the command "window>preferences";

The popup window "System preferences" opens. I check that the box "Sketchucation" is selected and then I tap on the button "Install extension..".

An other window is displaied to locate the .rbz file to upload, I select Sketchucation_v2.6.2-b11.rbz and I get it.

The last popup winwow is displaied "Extension installation is complete"

Then I have to restart SU.

I installed Sketchucation v.2.6.2 - b11 but I receive the message of error:

"Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/sketchUcloud.rb
uninitialized constant SUC::SCFapi
Error Loading File C:/Program Files (x86)/Google/Google SketchUp 8/Plugins/SketchUcation/SCF_loader.rb
uninitialized constant SUC::SCFapi
Error Loading File SketchUcation.rb
uninitialized constant SUC::SCFapi"

So nothing runs

Portos52 (Flintstone..)