Magento Version 18.104.22.168
Admin System Configuration Design Error
This a problem existed during a new installation.
Although everything seemed fine during the installation of a new theme I encounter the dreaded: “There was a problem processing your request” screen.
This was found to be a ‘cache’ issue and the fix is shown below.
Locate the following file.
In the file change the following line:
‘cache_dir’ => null,
‘cache_dir’ => “var/tmp/”,
You must then create a folder and assign write chmod permission 666: