Thank you for the update.
I've now filed a false positive report with AVG. Hopefully they can resolve the problem in a future database update. Juicebox users should not have to whitelist JuiceboxBuilder in order for it to work correctly.
The first time I got the error I was a bit concerned that Juicebox would replace my original image files.
You don't need to worry about that. JuiceboxBuilder will either copy your original images to the gallery's output folder (if the 'Resize Images' checkbox is deselected) or place resized copies of the original images in the gallery's output folder. Your original images will always remain untouched in their original locations.