We have just done as you asked and it seems to have solved the paypal issue at checkout. However now the shopping cart and paypal checkout page’s layouts are all wrong as its obviously trying to apply both the HelloSleek and default themes at once.
You can see an example of this by going here: http://www.cooldrives.com/index.php/checkout/cart/ after you add an item to the cart.
Can you please update the needed files? We’re happy that it works now but would like the necessary checkout pages to visually match the rest of the site.