Hey there, I'm trying to install version 1.8.3 of fec on a 1.3.7 zencart and I'm getting the following error:
Fatal error: Call to undefined function zen_get_multiple_tax_rates() in C:\xampp\htdocs\bmlc\includes\classes\order.php on line 450

I followed the instructions for 1.3.7, making the changes in the admin/includes/functions/general.php and admin/includes/languages/english/orders.php files and then followed the instructions for installing as directed by the readme.

step 1 - the JS Loader seemed to install ok, and step 2, upload all the files, fair enough, but step 3: then rename includes/templates/your_template to your template name seems odd. I already have a folder named for my template. Also all the files from the fec download have 'classic' as the folder name, was I meant to rename them or something?

I'm confused.

I searched the thread but only found a couple of posts asking something similar but the responses didn't make sense. I'm I just being stupid?