sqdge

My version also had this issue, but I think I found a fix.

In the VFB plugin directory go to includes/class-export.php

Around lines 577 – 583
Change:

if ( !isset( $_POST['action'] ) )
	return;
if ( $_POST['action'] !== 'visual_form_builder_export_entries_count' )
	return;

$form_id = absint( $_POST['id'] );

To:

if ( !isset( $_GET['action'] ) )
	return;
if ( $_GET['action'] !== 'visual_form_builder_export_entries_count' )
	return;

$form_id = absint( $_GET['id'] );

This seemed to work for me.