Add new field button -->
Uncaught SyntaxError: Unexpected token ; because field is empty:
<script type="text/javascript">
field_index = ;
Uncaught ReferenceError: field_index is not defined -> file:line fields.js:29
Temp fix for init errors:
Initialize vars with defaults values or dump an error notice; eg.
admin_head.php, line 11
$field_count = 0;
$options_html = array(); // For options object
PS: I don't have (or plugin don't install) the table {$wpdb->prefix}cfs_fields