Date picker missing + php error

[normasoft]

Hello,
we have bought premium Appointment Calendar plugin and have found a issues that weren't there in free version.
When clicked on Appointment button, popup appears without Date Picker, so I can't change the date there.
Also, when I select the service on the select input field, php error appears - Warning: Invalid argument supplied for foreach() in /home/clients/b2ae843d60a01adcae42bb8555534897/web/energiescielterre/wp-content/plugins/appointment-calendar-premium-3.6.5/appointment-calendar-shortcode.php on line 1192. None of these were happening in the free version which I used before.

Here's the page - http://art-cs.ch/energiescielterre/mes- ... structions

[normasoft]

As for the Date Picker, I chose Jquery datepicker instead of PHP. But still, I had to go into the appointment-calendar-shortcode.php and comment that line so I there would be no error seen. Why was it shown anyway?

[lkepchar]

I am getting the same error /wp-content/plugins/appointment-calendar-premium-3.6.5/appointment-calendar-shortcode.php on line 1192. How do I fix it? I need to be able choose staff members