Error 500 after upgrading to Joomla 3.7.1

Hi there, I'm using News Show Pro GK5 on my site, and it's been working great. Now I upgraded to Joomla 3.7.1 and also updated GK5 to 1.9.3.8.
I have two versions of GK5 modules - one for a list view, one for a slider view. All worked perfect. But after upgrading to Joomla 3.7.1 I get a permenant "Error 500" on the page with the GK5 slider module. With error reporting on in Joomla I get the following messages:

Notice: Undefined index: source_name in www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 42 Notice: Undefined index: engine_mode in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 44 Notice: Undefined index: include_jquery in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 47 Notice: Undefined index: list_title_limit in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 65 Notice: Undefined index: list_text_limit in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 65 Notice: Undefined index: news_header_enabled in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 73 Notice: Undefined index: news_image_enabled in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 74 Notice: Undefined index: news_text_enabled in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 75 Notice: Undefined index: news_info_enabled in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 76 Notice: Undefined index: news_info2_enabled in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 77 Notice: Undefined index: news_readmore_enabled in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 78 Notice: Undefined index: crop_rules in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helpers/gk.utils.php on line 104 Warning: require_once(/www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/data_sources//model.php): failed to open stream: No such file or directory in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 86 Fatal error: require_once(): Failed opening required '/www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/data_sources//model.php' (include_path='.:/usr/share/php:..') in /www/htdocs/w011ea55/j3xtest/modules/mod_news_pro_gk5/helper.php on line 86

Any idea what can be the source of this problem?

Thanks for any feedback

GavickPro / News-Show-Pro-GK5

Error 500 after upgrading to Joomla 3.7.1 #396