Hi Jack,
As per the issue description you are unable to install the add-in for Word.
I would like to ask few questions on the issue:
- What is the operating system installed on the computer?
- From which web-site are you trying to download this add-in?
Download the set-up file save it on the system, right click on the set-up file and click on Run as administrator and check if it helps.
The add-in seems to be non-Microsoft add-in. If you are trying to download it from a Microsoft site then provide us the link. If you are trying to download a non-Microsoft add-in then you may also contact the appropriate technical support for further help
on this issue.
I hope the above suggestion helps. If you need further assistance reply with more information and we will be glad to assist you.
Thank you.