[support] PayPal Gone Haywire?

I have a Drupal 5 site with E-Commerce 5.x-3.3 which has been up and working for while, like a year maybe. Today they write me and say people can't pay. I checked it out and the site is fine, BUT when I click to pay and it sends me to paypal.com, I get a blank page. IE and FF. I asked them to send me the password for their account so I can call PayPal and TRY to speak to a human, but do any humans here know anything about this? Seems to me that something happened at PayPal. Maybe it's just temporary? Thanks.