Fatal error- Uncaught Error

I had the Give Plugin working great on my test site and was looking forward to adding it to my live site. I installed the plugin and went to create my first form, and in the Donation Options box, under set donation or multi-level donation I see this “Fatal error: Uncaught Error: [] operator not supported for strings in /home/site/folder/wp-content/plugins/give/includes/formatting.php:443”
I doubled checked and I am using PHP version 7.1.0
It did not work to install it via a ZIP file. I tried to use FTP, but the plugin did not appear in the plugins list so I could activate it.
What is going wrong and how can I fix it?
Thank you!