getting a 404 error when I add items to the shopping cart

I found the thread that says debugging is included in 1.3.9, just look in the cache file. I did and there is nothing there but a sessionID that says "Installer keys.....".

The reason I need this is when I add items to the shopping cart and click go to checkout I get a 404 error.

This is a new install in a subfolder of a working store. I created a new database and exported/imported then recreated the store. This is the only real glitch I have so far.

The 'cache' dir. will give information on PHP coding errors. A 404 error means no page was found and for that, better to view your error logs from within your Hosting account.