Error Messages after saving edits: undefined index of slideshow_accordion.php

We are receiving the same error on random pages while editing random elements. It is not specific to one element or page.

So we would usually open a page in WP and edit some of the elements and press update and preview the pages. The updated page shows the following content and error. Nothing more:

Notice: Undefined index: index in /customers/7/3/7/thetradersroom.co.uk/httpd.www/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/slideshow_revolution.php on line 112 Notice: Undefined index: index in /customers/7/3/7/thetradersroom.co.uk/httpd.www/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/slideshow_revolution.php on line 115 Warning: Cannot modify header information – headers already sent by (output started at /customers/7/3/7/thetradersroom.co.uk/httpd.www/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/slideshow_revolution.php:112) in /customers/7/3/7/thetradersroom.co.uk/httpd.www/wp-admin/post.php on line 197 Warning: Cannot modify header information – headers already sent by (output started at /customers/7/3/7/thetradersroom.co.uk/httpd.www/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/slideshow_revolution.php:112) in /customers/7/3/7/thetradersroom.co.uk/httpd.www/wp-includes/pluggable.php on line 1210

Sometimes we go back to that page, undo the changes, save the page, repeat the same previous edits and then view the page, then the page would work and show the actual content that we edited but usually it does not work.

For example on our ETX Page and Marketing Opportunities page, the error is just constant, on other pages its constant. Our site is under construction mode however I have attached login details to our WP and hosting site. A screenshot of the error can be obtained be vieweing the Private Content.