The scroller button is there and when you click on it it lights up, but it doesn't scroll.
Someone who wrote a review on amazon.co.uk had the same problem: "I enjoyed playing the game until I realised I had a problem with my inventory. I could not pick up more than a certain amount of items and I had no possibility to drop any of them. I had to restart a new game many times and in the end I had to complete it with the walkthrough in hand so I would not pick up any unecessary items. So very frustrating experience overall."
I experimented and determined that the inventory items are there, but unviewable and unselectable because you can't scroll to them.