Array Offset Errors?

Hi Everyone,

I hope you can help me, I’m making this website for a client and have all of a sudden come up with these errors with this plugin. Its been working perfectly fine up to now and I’ve change all settings and restore from backups and things that may have caused it but still cannot get it to work. Is anyone able to help or if they know what I can fix to make it work?

Every item has this above it: ‘Warning: Undefined array key “split_gift_hide_total_price” in /homepages/42/d823430783/htdocs/clickandbuilds/TheWeddingofAdamandChloe/wp-content/plugins/wpgiftregistry/templates/wishlist–single.php on line 42’

and on the backend on every single page at the top it says:
‘Warning: Trying to access array offset on value of type bool in /homepages/42/d823430783/htdocs/clickandbuilds/TheWeddingofAdamandChloe/wp-content/plugins/wpgiftregistry/admin/class-wp-gift-registry-admin.php on line 330

Warning: Trying to access array offset on value of type bool in /homepages/42/d823430783/htdocs/clickandbuilds/TheWeddingofAdamandChloe/wp-content/plugins/wpgiftregistry/admin/class-wp-gift-registry-admin.php on line 331

Warning: Trying to access array offset on value of type bool in /homepages/42/d823430783/htdocs/clickandbuilds/TheWeddingofAdamandChloe/wp-content/plugins/wpgiftregistry/admin/class-wp-gift-registry-admin.php on line 876

Warning: Trying to access array offset on value of type bool in /homepages/42/d823430783/htdocs/clickandbuilds/TheWeddingofAdamandChloe/wp-content/plugins/wpgiftregistry/admin/class-wp-gift-registry-admin.php on line 877`’

Ive gone through all of the PHP files and can’t see, to find anything wrong at all and I haven’t changed anything that’d affect it.

Any help would be greatly appreciated.

The page I need help with: [log in to see the link]