OK, I re-uploaded the original index.php and now there are no more errors.
The old theme works, but when I shift to the new theme (pure-simple) all is white again on the front end. On my end(admin) everything looks sharp.
What to adjust to get the theme (or any other theme) working?
Is it in my database somewhere or …?
Could I start over somewhere somehow?
ok, now it got worse..I probably used the wrong index.php..
I can’t change into the old theme either anymore, it gives a syntax error in index.php line 17. where the adjustment was made.