Download button won't work

site is
https://secure.netsolhost.com/rtswinc.com/Store/cart/

To see problem create a user name and password
then log in an select RTS Code Modules from the Our Products area.
This is a testing site only. use credit card as the payment type and use this test card number to make the purchase 4111111111111111 and an experation date of any day into the future. You'll see the download button show up but the page ends up in a 500 error.

permissions on Pub and Download folder are set to 777
There is a green led next to the file name in the attributes
Attributes are set to download on, redirect true, streaming false
file is a small zip file placed in the downloads folder

Error message is
The proxy server could not handle the request
GET /Store/cart/pub/.ifogkxbpdkfjdk/test.zip
Reason: Host not found

If anyone could help me with this I would appreciate it. I've been looking around in the forums and so far have not been able to get it to work. I did try setting the redirect to false and when I do that I get a blank html page

PS I know the site is working slow due to network solutions set up I had to run the whole store in SSL. I will be switching to a dedicated SSL certificate once I can get the other features working right. If it still runs crappy I'll have to switch to another host which will be difficult to convince my boss to do.

You can ignore the previous entry. The problem was the application won't work properly with a shared SSL certificate at least not with Network Solutions host. I'll be switching over to a dedicated SSL certificate soon and currently the site works fine in non-ssl mode. I won't be going live with this site to customers until I get the app to work in SSL.

I have always used shared certificates without a problem ... I'd be talking to my host and see what the heck their problem is ... :unsure: