Sorry it took so long, I'm out of town. However I was able to get this fixed for you.
Whenever you have a blank page, the first thing I do is turn on error messages with this code on the top of the page:
This displayed an error with a missing image: installed.png
That is an old error that we have fixed in the latest version where it gets identified as a malicious file and deleted. The solution was to update the theme_open.php file. The site is working now.