First of all, thank you lhungil and DrByte and for replying to my post. Without your responses, the world would seem a much colder, lonelier place.

Next, I have fixed the problem and have been successfully processing orders for a few days now. Now that the dust has settled and I am sure of what happened, I want to share it with the rest of the world in case someone else runs into this.

The problem was that my site was being hosted on a server at GoDaddy that did not support anything BUT SSL. So even though I put in all the changes recommended by Dr Byte back in the fall, all it did was allow ZC to negotiate with PayPal to select the best AVAILABLE protocol.

So, as long as PayPal supported at least one version of SSL, all was fine. But on Jan 12, PayPal disabled support for the last SSL version. Hence my site broke. No helpful error messages from ZC on what was causing the problem. No tech support from GoDaddy whatsoever. PayPal tech support was concerned but only slightly helpful. I read and re-read Dr Byte's description of what the fix did (thank you for that - it saved my ########), and then I made a wild ###### guess that maybe there was no TLS on my server. Luckily, that turned out to be right.

The only solution was to move my site as quickly as possible to a new server that supported TLS. Very painful, especially under pressure and with my site mostly down--well, at least all the SSL pages which turned out to be key. So, first, I turned off SSL on my storefront and removed the PayPal payment modules and left only the one for "Pay by Check or By Phone". Then I added a Checkout note to my customers about POODLE and asked them to call in their payments. Kinda hokey, but amazingly, people actually did that!

But then, I was left with the problem of how to submit the orders to shipping without the admin screens or the email confirmations (which weren't being sent either). I managed to figure out the details by looking at about 4 DB tables for each order. Whew! That gave me a whole new appreciation for the work that ZC does! It took quite a while to process each order, and it was error-prone, but it was doable.

In between orders, I started migrating to a new server, but it did not go smoothly. The new server had an unfamiliar CPANEL interface and a new version of PHP and several other important differences which I discovered one by one. The worst problem was getting an SSL certificate to work. This took about 3 days. GoDaddy tech support claimed it was set up correctly on their end, but it was not. Once GoDaddy saw I was using ZC, they basically they told me to go pound salt, since ZC is a 3rd party software app which they don't support and therefore it must be the problem.

In the end, there was a setting that I needed in the CPANEL which had been overlooked. GoDaddy tech support should have spotted it, but they were so busy pointing fingers at ZC that they did not bother to even check. I finally convinced them to take a look at the settings by putting a stupid jpg image one level up above my ZC code. When displayed with http://___.jpg all was fine, but with https://___.jpg it was broken. Since no ZC code was anywhere nearby, they finally were convinced that their SSL certificate was not set up right and then fixed the problem in about 2 minutes. So basically my site was down for 3 days due to bad GoDaddy tech support.

Once my site was up and running with TLS on the new server, I then had to change the way I send email (I now use SMTPAUTH instead of sendmail) and reinstall one of my PayPal payment modules. And Order Time is not being displayed correctly in the admin section -- it thinks we are on GMT. I tried to put in some extra configuration files which I found on the forum, but they broke my site, so I am living with it for now. Any suggestions on something that will work for 1.5.1 would be appreciated.

And lastly (this is not yet fixed) I am getting PayPal Instant Payment Notification Warnings occasionally like this:

Code:
Please check your server that handles PayPal Instant Payment Notifications (IPN). IPNs sent to the following URL(s) are failing:
http://keylessentrylocks.com/ipn_main_handler.php
https://keylessentrylocks.com/ipn_main_handler.php
This seems to have the effect of occasionally not updating the order status on my site after checkout. I'll call PayPal Tech Support about this one, but if it is familiar to anyone out there. please let me know.

Oh, one more thing is still wrong on the new site. I get an error message after I sign up a new customer. It only happens intermittently and their account is still created and their order goes through fine, so it is not a critical problem at the moment. But I would still like it fixed. If you have any ideas about that, plz let me know. Since these last 2 items are intermittent, I am thinking it might be related to a server resource instead of a code issue.

Hope that made sense.

Thanks again, guys!