Sorry I was slow to respond.
Here’s what the developers told me (and I did get it all straightened out, so it helped):
That error is usually a problem with the Paypal API credentials. Can you verify that you have completed the steps listed here? https://cms.paypal.com/us/cgi-bin/?cmd=_render-content&content_ID=developer/e_howto_api_ECAPICredentials
Also, there are different credentials for Sandbox mode (for testing) and Live mode. If you try to use the Sandbox credentials while running live, you might see this error.
Sorry, maybe I’m missing something. I copied and pasted the code you included here, and nothing changed. I tried different column numbers and different percentages, but the table looks exactly the same.
