It took me about a million times, but the "walk up to it, press Z, select your potion (I went around the wheel once cause it wouldn't let me select what I was already on), then push Z again" worked for me. I had to do it three times then Harry finally drank from the cauldron. Jeeze.

It took me about a million tries, but the "walk up to it, press Z, select your potion (I went around the wheel once cause it wouldn't let me select what I was already on), then push Z again" worked for me. I had to do it three times before Harry finally drank from the cauldron.