Cannot export to csv or xml from Formmaker?

I used to be able to export the submissions from the Forms through the Form Maker plugin. But now it doesnt work anymore? I’ve tried on Firefox and Chrome, but basically both do the same. As soon as I click on export to xml (or csv = the same), the browser opens a new page: http://nca.org.sg/wp-admin/admin-ajax.php?action=generete_xml&form_id=14 and that’s it.
I am organizing events and really need the attendance lists…