Hello, I saw some similar posts but they were closed, so here we go...

I tried to install the Fast and Easy checkout for Zen Cart and that is where my problems began. Every time I proceed to step 2 of checkout I get the following error:

Fatal error: Call to undefined method order_total::collect_posts() in .../includes/modules/pages/checkout_payment/header_php.php on line 88

That is the same error message that comes up when I did the debug error logging utility.

I am the biggest idiot in the world and didn't do a fresh backup before beginning the install, but even so, I have since uploaded my older backups via FTP for both /admin and /includes (the only 2 directories the addon altered...I think), but the checkout process is still not working.

Any help on this matter would be greatly appreciated, I am at a loss on how to fix this.

I only had a few customizations from the original zen cart, however would installing the new version be faster than a temporary fix? We just sent out a large mailing inviting mail order customers to order online so this is bad timing, I would prefer having the checkout work for this week and worry about upgrading (which I feel is needed) next week.

website is naturalcupboard.com, thanks for any help.