I click to buy an item and get this error:

Can't enlarge image so here is text: Fatal error: Call to a member function update() on a non-object in /www/subeta.net/games/reading_prizes.php on line 38

Edit: It turns out that I am actually buying things as I have them in my inventory. Unfortunately I bought 2 of something as I didn't think it was working :(

Same thing happened to me, I have two of a thing now as well

I just made a ticket and then remembered to check here. I have the same problem and of course also 2 items of which I only needed one :(