The main error message is telling you it can't load ' extensions.rb'
Many Plugins will require that file as they load.
It belongs in the main 'Tools' subfolder.
This copy/pasted into the Ruby Console will open it for you.
UI.openURL("file:////#{Sketchup.find_support_file('Tools')}")
This is typically:
C:\Program Files (x86)\SketchUp\SketchUp 2014\Tools
But it might vary depending on your system and installation preferences...
That folder must contain three .rb files.
These ship with SketchUp and install as part of its standard installation package
extensions.rb sketchup.rb langhandler.rb
It also contains the ' RubyStdLib' subfolder, containing the latest Ruby files.
The three files should NEVER be in the Plugins folder...
You should never use copies of these files from earlier SketchUp versions as they are not necessarily the same code...
As you have ' Ruby' related errors too, then I suspect another potential issue... perhaps you have not upgraded v2014 ?
The initial v2014M0 had a known issue...
This is that if you launch SketchUp by opening a SKP that is on a drive that is NOT the same as the SketchUp.exe drive letter it messes up the $: and that causes issues with the Ruby files loading...
If this is the case get the latest v2014M1 and install that...
Typing $: in the Ruby Console should return a list of folder paths including the main ../Tools and ../Tools/RubyStdLib folders, if these do NOT have the same drive letter - e.g. C:, then it means you do not have v2014M1 installed, since that update fixed this issue.
Note that opening SketchUp from the menu and then opening a SKP should NOT produce such errors in v2014M0...
But if you have messed around with folder contents etc it's a sure recipe for disaster!
Try repairing the SketchUp installation, hopefully the missing files will return ???