Ok I fixed it. In case you are having the same problem, you need to go into that file mentioned in the warning. So that end file is called admin-interface.php
Code edit it, scroll down to line 1214 that the warning is talking about.
You will see
$oldorder = $slide[‘order’];
Replace it with this:
$oldorder = isset($slide[‘order’]) ? $slide[‘order’] : ”;
Problem solved. Here’s the part from another forum that fixed it.
“The second issue is as follow.
Warning: Illegal string offset ‘order’ in /path/wp-content/themes/wp-metric/admin/admin-interface.php on line 1155
Answer: the reason here is because you are trying to get an array key which does not exists on the wp_options from db and on php 5.4+ they are trying to deprecate loose key references, i.e., without quotes.
Fix:
#replace
$oldorder = $slide[‘order’];
#with
$oldorder = isset($slide[‘order’]) ? $slide[‘order’] : ”;
Now I think it works well with php5.4+ at least as far as I can see :).”