To install the tools you will need write access to the local Notes data directory.
Depending on your machine's setup and organisation's domain policies you may not have access to write to the local Notes data directory by default, even if your account has local admin rights.
Starting Notes with Run as Administrator elevates your rights above local admin and often resolves installation permissions issues in Windows.
Right click on your Notes icon and select Run as Administrator.
If you are dragging widgets from the browser you will probably need to start the browser with Run as Administrator as well.
If you are using the local widget installer then you may not need to start Notes with Run as Administrator.
If your Windows installation does not show you these options, then please contact your service desk for further assistance.