PHP Errors

I have been receiving this error on my site:

Warning: json_decode() expects parameter 1 to be string, array given in …/wp-content/plugins/advanced-form-integration/includes/functions-adfoin.php on line 264.

I removed the rest of the URL it provides, but that should be sufficient to locate the error. Is there something I need to do to address this issue? Is it impacting functionality?

Thanks!