Download Assistant Issues: Unable to Reinstall Dorico 4

I’m a student with the Open University and have downloaded Dorico 4 once successfully, but then suffered P.C issues and had to download it again. I can get to the download page, but everytime I do, it gives me an error message pertaining the Steinberg subfolder in my Downloads folder and says “directory name invalid” and I can’t actually download anything.

Can anyone help? I’ve been battling with this for two days.

Thanks.