The "File Not Found: Screen Savers" error is easy to correct. Please follow these steps:
Open your hard drive icon.
At the top of the newly-opened window click the icon titled "Home".
The caption of the window should now be the name of your user account.
You should see a folder named "Library". Open the Library folder. There's more than one Library folder on your computer. You need to be sure to open the Library folder under your USER ACCOUNT.
If you do not have a folder titled "Screen Savers" (minus the quotation marks) then you will need to create it in the "Library" folder.
Run the installer again.