Flexi Custom Code - Awesome PHP Code Insertion Module

Today I will introduce a free module for adding PHP, HTML, CSS or JS code.
Unfortunately the developer of this module has stopped working, but it still works on Joomla 4 - Simply because this module is not complicated.
I have used many Custom modules, but this is the only one that supports PHP language. Make you comfortable to customize the website (Of course if you know PHP - LOL).
This module is now out of JED, fortunately I have a backup. You can download it below:
Flexi Custom Code - Joomla 3 & 4 Flexi Custom Code - Joomla 2.5
I will have a series of articles related to PHP and will use this module.
I migrated about a thousand items with attachments from K2 using your tool and attachments plugin. I initially did this on a test account. Everything worked fine over there. The migrated article attachments worked fine. Then I backed it all up and moved it to my live domain. Now none of the attachments load. All I get is Exception File Not Found and I can't figure out where to look. Turning on error reporting and debug don't tell me anything. I am guessing the old files were not moved during the migration correct? Or how does that all work? I still have all the original folders in the original places as far as I can tell.
An error has occurred. 0 implode(): Argument #2 ($array) must be of type ?array, string given
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Any idea what's causing this?