i had a similar issue with vectorworks. turns out that a security setting had to temporarily changed on my computer.
i tried the same thing with your tutorials and it worked as well.
apparently something was set up wrong with the file to be downloaded. vectorworks said they "fixed" it so changing settings wouldn't be required in the future, but i don't know what they actually did.
a more pressing issue for me is that i applied for an academic license, and haven't received an answer. maybe it went to spam, where i found your notice. my trial version ends in four days. so i would like to get the academic version resolved. how should i go about resolving that.
thanks,
ray