Custom Field Upgrade not working

Hello,
I purchased the custom field uploader upgrader last night and followed your installation and operation instructions. However after adding the custom fields they still don’t appear when I am trying to map the CSV file in the CSV import pluggin. I don’t know if this helps but when I add the custom field (my_custom_field) and press save I don’t get any new messages it just returns to the initial screen and has “list your customfields comma seperated” in the input box.
Thanks in advance.
Damian

http://wordpress.org/plugins/woocommerce-csvimport/