Actually it's interesting that you say that, because it looks like they are using version 1.3.8. But they were having that duplicate order id (order ids not properly passing to the invoice id in the gateway) issue, so I located the thread in the forums and replaced the files.

I was not the original Zencart developer on this site; I was only hired to do some gateway integration and troubleshoot some other settings. I wonder if the developer they have in China maybe had some incorrect configurations in there, or maybe they had mistakenly uninstalled the AIM mod and reinstalled an older one....the one that was there when I acquired access last week did not have any of the latest features including MD5 Hash option.

Thanks again.