UPDATED:::: can you actually email that tar.gz to me, it would help. I get an email like this once every couple weeks and although that's a tiny slice of downloaders, I really don't know what is causing it.
Previously I wrote here that it had to do with browsers breaking up the download into multiple downloads, but to my surprise I went to rewrite the relevant code on the site and I had already done it back on March 21st. Which explains why I haven't gotten as many of those emails lately. 😃
So, the download link will work the first time, and any number of times for the 5 minutes thereafter. Meaning that if you are downloading the tar.gz on your first attempt, or within 5 minutes of your first attempt, it will work. If you're attempting to download the app more than five minutes after your first time clicking that same link, you'll get taken to an HTML page on the Sideview site with an error message.
One wild guess is that you're downloading the app to your browser, and then saving the URL into your clipboard and using it in a wget call more than 5 minutes later. The response at that time would be the aforementioned HTML page, but if you were saving it as sideview_utils.tar.gz, indeed gunzip wouldn't like it very much.
