Insert Order - Error When I Try to Add a Product [Solved]

When I try to make a new Order I can never add a product. When I do the an Error box pops up! I have tried looking it up a few times though out the forums and came a across a few reasons what it might be, such as my config.php files not setting the HTTP/HTTPS right. I went through them and they all seem to be correct. I am running 1.5.2.1

Any ideas?

EDIT: I get this error-
The page at https://fuelcellsetc .com/store/XXXXXX/index.php route=sale/order/update&token=ddb5b9125101dbaff7093e139acc7a20&order_id=157 displayed insecure content from http://fuelcellsetc .com/store/index.php?route=checkout/manual&token=ddb5b9125101dbaff7093e139acc7a20.

jquery-1.7.1.min.js:4
XMLHttpRequest cannot load http://fuelcellsetc .com/store/index.php?route=checkout/manual&token=ddb5b9125101dbaff7093e139acc7a20. Origin https://fuelcellsetc.com is not allowed by Access-Control-Allow-Origin. index.php:1

I've changed the name of my admin folder to something else if that helps.

We need:
-Your opencart version?
-Update or new install?

My Opencart version is 1.5.2.1 and I have not recently updated it. It has been up and running for about 6-8 months now.

Anyone have any idea?

avvici wrote:We need:
-Your opencart version?
-Update or new install?

My Opencart version is 1.5.2.1 and I have not recently updated it. It has been up and running for about 6-8 months now.

Solved by updating OpenCart to 1.5.5