Checkout Error

Hi there: I am getting an error on the "/store/shopping-cart/checkout/" page...

<There was a problem connecting to PayPal to setup your purchase. Please try again.

10002 - Security error - Security header is not valid>

Any Ideas on what is up?

Also I am using PayPal for checkout. Is there a way to remove the shipping form from the checkout process?

Thx Much!

Rob