cart page is blank

i have entered payment and shipping methods, plus products, but lately, for some reason, when you add anything to the cart, then click View Cart, the page is blank????

http://hoospref.biz
add any product, then this is the cart page that is blank
http://hoopsref.biz/index.php?route=checkout/cart

probably one simple setting, just cant figure it out

also, after upgrading to 1.5.4 it now says in the admin panel
Warning: Install folder still exists and should be deleted for security reasons!

i thought the newest version had Google Payments integrated already, but it doesnt appear to, thoughts?


thank you, OC novice

1) there seems to be a problem with your install location. I get a 404 and then a blank page.
2) Delete your install folder completely after install. It's a major security risk.