I bought kontakt yesterday, installed on my amd 64 4400 dual core machine running win xp.
I updated kontakt to 2.1 with the download from their site. I can get sounds, but the programs don't run well. If I click to change to a different folder in kontakt, the window freezes, and I need to toggle to another window and back to see the change made. Also, in PT, I can't select midi data easily, the cursor just kind of gets stuck and won't move.
I changed buffer settings, changed from 2 to 1 processors.
At first I thought it was just kontakt, but then I started having the same problem with sampletank, too.