12 Dec
2008
12 Dec
'08
11:55 a.m.
Seems that's it. Thank you!!
It is most likely the URL which you are being redirected to on Paypal. The old method which 3.x uses has been removed from use on PayPal.
You will need to update the url to https://www.paypal.com/cgi-bin/ webscr which should fix the problem