Unfortunately the trial thing is a challenge because the themes are created, owned and hosted by authors and a functional trial set up is a bigger job to activate (on the scale of envato traffic) than it seems, and even then these tend not to supply files to install on a 3rd party host anyhow.
While WP can be used on a Windows server it’s almost always going to be more complicated esp on a shared environment from someone like GoDaddy.
I am pretty sure that you may end up with the same issues you had with Jupiter (which FYI is a highly regarded theme) when trying others too. It sounds more like a hosting obstacle than the theme.
Could you setup a separate hosting package using Linux for the purpose of the blog site and link through from there to the other activity?