I have no idea how/ why the ?main_page= part? gets added, I just deleted it in browser back to
http://pinewoodforge.com/zencart/index.php and got the same blank result though.
I agree about needing to decide on a method, one person in this discussion suggested using Dreamweaver, and since I am familiar w/ it that's my first choice, but I think stevesh recommended against it......
I found a file called 'error logs' in cPanel, perhaps this is what you meant, sure enough it had gobs of 'does not exist' messages, such as:
[Sun Mar 02 19:56:37 2014] [error] [client 67.84.182.144] File does not exist: /home/pinewood/public_html/403.shtml, referer:
https://www.google.com/
but nothing i could see that was useful. thanks, del