I am able to download the add-ons and unzip them manually from the website.
I checked the internet options and it was set at Medium-High. I set to medium and retried, unfortunately same issue (but hey, it was something I hadn't tried, so it was worth a shot
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The only other thing I can think of for JAVA is that I do use "MapTools" (online rpg freeware) and to get it to work correctly I actually have to have an older java installed at the same time as the newest java. Normally most stuff uses the newest version and I manually set MapTools to use the older one, but it is out of the ordinary...