I've almost completed a project using zen cart. But I'm having huge problems getting paypal to play nicely. I am constantly confronted with the following screen when I try to check out.
I've re-installed the paypal module several times, ensure that there were no errors that I could find. I even installed the 1.3.7 patch that Dr. Byte posted. Yet I'm still facing this error. So does anyone have any ideas on what can be done to fix this.