I cant login in the backend

Hello,

unfortunately I get this failure: Fatal error: Call to a member function get() on a non-object in /homepages/39/d466972252/htdocs/administrator/templates/isis/error.php on line 114

How can I solve the problem?

concerning:
http://my-website/administrator

best regards
Annett

Did you install something before that happened?

I only modified the logo and the 4 images with the watermark. I uploaded the images via ftp in the right folder. I got another failure as I created a new user.

failure: Invalid Token on this side:
http://my-website/index.php/login?task=user.login

best regards
Annett

If you did small work after hot start best you simply install again , because we would otherwise need to charge you for fixing if you would hire us for fix job.

I installed the template again