Iono is payment system is provided by http://olate.co.uk 
Google search keyword: Powered by iono
I checked newest version and show more files are in error:
http://[domain]/[path]/templates/iono/admin/denied.tpl.php 
http://[domain]/[path]/templates/iono/admin/index.tpl.php 
........
All file in /templates/[filename]
And sub directory /templates/sub-dir/[filename]