Do NOT use the programfiles folder for the SDK! The programfiles folder is a restricted folder in Windows. That´s the reason for your ACCESS DENIED errors.
Create a Folder C:\Android and use this instead. Or any folder on another Drive D:\Android / E:\Android,
You can find the Setup-Instructions here.
https://www.b4x.com/b4a.html
You also can watch this Video as it describes it clearly.
Start with a new Blank folder like you see in the Video.