Cannot Proceed Past Step 2 of Checkout after trying Fast and Easy Checkout

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.

1. Yes, upgrading is seriously needed.

2. This is where I'd start: http://www.zen-cart.com/wiki/index.php/Troubleshoot_-_Diagnosing_Obscure_Issues and since you said you have no backups at all to work from, you'll need to use the original Zen Cart files as your comparison.

Thanks for the quick reply DrByte, you are the best. I do have backups but they are a couple months old, is that not a good idea to use those? Also, is comparing the folders for differences still necessary if I just do an upgrade to the latest Zen Cart? Thanks again for your help.

If you're wanting to get your current store up and running again quickly, I would likely use your latest backup as a guide. Unless you think the PHP files in that backup are unreliable.

If you don't mind staying down while you build a separate new store to test your 1.5.0 upgrade, then you've got that option too. Don't upgrade your live store to a new version directly without staging it elsewhere first so that you know it's working correctly before you touch your live store with it.

Thanks DrByte! I used winmerge to compare mine with an original 1.3.7 download and noticed the text was different in /includes/classes/order_total.php, and since my error message mentions order_total, I tried changing that one first, and voila! The checkout works again!

I will be upgrading to 1.5.0 this weekend, but this will hold me over for the next couple days till I can make the changes during a down time.

Thanks again, you're awesome!