I went to the site and added the product to the cart and got a warning that the ssl cert did not belong to baklava.com but belongs to *sslcert19.com (at least I think that is what it was). None of the first shopping cart screen should be secure since there is not critical data there that needs to be protected. So your template for this page needs to just use
http://baklava.com/store/shopsite-images/...
instead of
https://baklava.com/store/shopsite-images/...
This will avoid the issue on the first shopping cart screen. Note that I think it is ok to have secure images on a non-secure page and no warning would be issued except for the cert not matching the domain name for your store.
On the second shopping cart screen (billing.cgi) you have a reference to
<link rel="stylesheet" type="text/css" href="http://www.baklava.com/style3.css">
I'm not sure if that would cause a warning or not but it might.
There are a lot of links to http pages but I think those are ok.
There is also a form submit that goes to a non-secure page
<form METHOD="POST"action="http://baklava.com/cgi-bin/sc/productsearch.cgi?storeid=*1ab6811a40049d2203817ccf755a8d" style="font-family: Verdana; font-size: 8pt">
I don't know if that would cause a problem but you might try changing it to see if it makes a difference.
I also see that you are referring to both
www.baklava.com and baklava.com note that these are 2 different domain names NOT the same. This might also cause a problem with a cert for your actual domain once you get the valid one. So make sure you get the cert for the appropriate domain name and change any references to the other one so you only point to one domain not two.
Also note that there are 5 or so sections in the shopping cart custom template. You need to make your secure changes in all of them exceept the [-- DEFINE SHOPPING_CART --] and [-- DEFINE THANKYOU_EMAIL --]. These two should not use secure urls.