Hi faissca
This error relates to Joomla backend, not the issue of JA ACM module, you can fix it with this tweak:
1) Go to file: /modules/mod_ja_acm/admin/fields/jaacm.php
2) Add this line of code to line 46:
JHtml::_('script', 'media/media/js/mediafield.min.js', array('version' => 'auto', 'relative' => true));
It will look like this:
I also attached this file here so you can see the difference: