Problems with eNewsletter crashing and error messages.

E-newsletter has stopped working on one of our sites.
I turned on debugging and received an error message related to "e-newsletter\email-newsletter-files\builder\class.builder.php on line 368".

I cloned the site to my local server and it started working again. I assume this is because the live site is on shared hosting; resources and what not!

I have done all the usual checks, disabling other plugins and switching themes.

The debug info that shows up is :
Notice: Trying to get property of non-object in C:\Program Files (x86)\Ampps\www\bht_test\wp-content\plugins\e-newsletter\email-newsletter-files\builder\class.builder.php on line 368

and if I try to edit a newsletter or create a new one I get the following notice in addition to the first one:
Notice: WP_Customize_Manager::remove_panel was called incorrectly. Removing widgets manually will cause PHP warnings. Use the customize_loaded_components filter instead. Please see Debugging in WordPress for more information. (This message was added in version 4.5.) in C:\Program Files (x86)\Ampps\www\bht_test\wp-includes\functions.php on line 3897

I have seen another post in the forum with exactly the same issue.