The most recent fix I tried was to delete the users/battlenet folder. Now instead of "failed to download a required file" the message has changed to simply "failed to download", I am not sure if this has any significance. After I check that "failed to download" box, another error (700) appears, if I close that, then the application closes.
If I try to launch through the diablo 3 launcher or diablo 3 files, I get the failed to setup tools error.
I tried another fix, I moved my diablo3 file to a different folder and tried to re install after deleting users/battlenet, when I tried re installing, I received the streaming error. So I moved the folder back and tried more troubleshooting on my original file, but nothing seems to work.
Please help me out, I am planning on calling tech support when I get time.