Did you ever solve this problem ?, cuz im having the same problem aswell.

No, no solution yet!
I did do one thing, I made a backup of the database from the interface of my hosting company! so at least I have some kind of backup!

I also installed the addon "backup" from the marketplace, but this has the same result as the original backup! - error 500

I really don´t feel good having backup not running! Especially as it is a client site with lots of content!
All my other concrete5 installs with same hosting company work fine! It´s just this one!

Hope we get some more attention with that!

hmm very strange. I have multiple installations too, but the one that is hosted by concrete5 doesn't work.. :(

That´s really strange, cause that means the problem can´t be within the core of the concrete5 installation?
You got anything else special?
I got "shadowbox" and "reflection.js"

No nothing special. I have made some small modifications to the login.php and page_not_found.php files. Thats all. I have made ticket for the concrete5 server team. Maybe they can help with this problem.

So did you solve that problem meanwhille? Actually I´m having that Problem on all my concrete5 installations now! :(

Thanks, sounds good, I will check it out!