For the avoidance of doubt...
You should not be running SketchUp itself as the administrator - although as an ordinary user you can have administrator powers.
The SketchUp exe file properties should also NOT be reset to 'always run as administrator', as this elevates SketchUp's process above that of Windows Explorer, creating unexpected issues.
You MUST install SketchUp properly.
Doing it in other ways leads to unexpected and unpredictable issues - the errors you see are indicative of an incorrect installation.
Please follow these steps carefully.
Close SketchUp.
Find the SketchUp installer's exe file - probably in your Downloads folder ?
Select its icon.
Right-click > Context-menu >
"Run as administrator"
When prompted choose "Repair"
When you restart SketchUp it should be installed correctly and avoid these errors.
However, if it does not try this...
Close SketchUp.
Find the folder:
C:/Users/Marianne/AppData/Roaming/SketchUp/SketchUp 2017/SketchUp/Plugins/
The users AppData path is hidden, but is accessible.
Go up one level and select the Plugins folder's icon.
Right-click > Context-menu > Properties > Security [tab] > Edit [button]
Ensure all of the groups/users listed have the "Full control" [topmost permission] checked.
Apply/Save the changes, and the settings should ripple down to all files and subfolders etc.
Restart SketchUp - any better ?