bwaymark

Probably way to late, but as I ran into the same problem and just figured out I thought I'd mention that I was getting the same problem and the probable was that I didn't quite follow the instructions and put the "add_cart" function in the wrong place (under the update function, not the add function) .... only took me a day and a half to figure that one out! That'll teach me to read more carefully! Go bad and read that line of the upgrade instructions and you'll see what I mean.