Sorry to undig the topic, but I thought some other people like me might want to give a try at this script ... and spend hours (like me) trying to make it work. lol
I actually did ! It works now. If you want, I can try to help people who encounter problems.
In your specific problem, romanthebrain, I think you need to enable global variables in your php.ini, like said before. It worked for me.
Now, I will try to work on and "add to cart" system, or maybe optimize the code like tried above to remove the global variables.
And eventually, make a guide on all the problems one can encounter with this script.
btw, thank you to the maker of this script !
regnakhan any chance you could upload the working version you have for 2.2 so that we don't have to go through the 7 pages trying to work out the issues?