Urgent: Single Payment Option not working

In our store (ZenCart 1.3.7) we only want to provide a single payment option. However, whenever we do this the user cannot get past Step 2 of checkout. It responds with an error saying that A Payment Method Must Be Selected For Your Order. However, there is no radio button shown to select this.

How do I make this work? I've tried several different payment options by themselves, and it always does the same thing. If I have more than one option, everything is rosy.

The client on this is getting antsy so any help would be appreciated!

Thanks for your help!
Lonnie

Since the functionality you describe works perfectly fine out-of-the-box with built-in payment modules and the default template, something's broken with the customizations you've made to your site.
Can you please list all the ways in which your site is different from a fresh brand new uncustomized install without any addons or settings changes?

Thanks for the quick reply!

Unfortunately, it's been a while since we worked on this site and somehow missed that this was broken. I think it's because the client took several months to actually take care of a couple things on their end.

From what I recall, the only changes we made were to the template/skin. We installed the UPS and Fedex shipping modules and I believe that's it.

http://mid-americahardwoods.com/store/

Do you happen to know what file that display would be in and I can check it out?

Thanks!

Well, it would be in any file you've changed from the original code, or in any template/override file you've added which intercepts the original code.

I suppose a "starting" point would be to look at all template files that contain "checkout" in their name, and all the files/folders under /includes/modules/pages/ that include "checkout" in their name, and see what's been changed and why.

WinMerge is a handy free tool for finding changes.

If that doesn't reveal anything, compare your entire site ... all files, all admin settings, all addons, everything.