Permissions permissions & permissions ..
Running as Admin eliminates a lot of these issues, which is why it is suggested often.
Just my thoughts.
Do you NEED to Run as Admin .. I dunno, depends on many system settings
Can it hurt to do so .. probably not in my experience with PG Products.
Anytime I see 'Access is Denied' I immediately check the related permissions next.
Not much else causes this error.

You can grant access to specific users, but generally the Admin user has access already.