array_key_exists ERROR updating to GS 3.2.1

[D.O.]

Hi Shawn,
As I said I copied only the admin folder without index.php because I didn't want to overwrite other important folders of my site.
Most probably, Carlos figured out my wrong "steps".
About your idea, I like it: index.php should includes another file in the admin folder, just to avoid problems like this.
The Problem is fixed.
Thanks for your help!