Custom field checkbox not working

Hello,

site address: http://entertain.co.nf/

I am using the custom fields feature to try and create check boxes with the skills a person has. I have set up 5 so far to choose from (a performer can have multiple) to help customers make their choice.

When selecting one or more of these receive the following error:

“Warning: trim() expects parameter 1 to be string, array given in /srv/disk9/1697989/www/entertain.co.nf/wp-content/plugins/ultimate-product-catalogue/Functions/Update_Admin_Databases.php on line 587”

and the selected checkboxes do not save.

Am I configuring this incorrectly or is there a big in the code?

The purpose of this is to allow people to select performers based on the following hierarchy

Category: State Location
Sub Category: Region
Tags: Character type (clown, fairy, etc…)
Custom Fields: Skills (magic, balloon bending, face painting, etc…)

Thanks for your help
Jasha

https://wordpress.org/plugins/ultimate-product-catalogue/