We've had some reports in the last week of strange errors appearing on Windows clients relating to banners. I can't paste screenshots here but one had a script error:

URL: https://downloads.hansaworld.com/downloads/static/marketplace/js/bgiframe.js

and the other is getting a file download prompt:

Do you want to save this file, or find a program online to open it?
Name: WebHWMasterBanner.hal
Type: Unknown type
From: www.hansaworld.com

Any ideas why these types of messages have started appearing, and how we can stop it? It's causing disruption for customers.