Hey bettymoo,
unfortunately I don't know what to do, but fortunately for you there's at least another one -- me -- who got the same problem. I observed, that it is mostly the buttons on the stick, not on the thrust control. I played around a lot with different drivers, but I soon got the feeling, that it became worse. I manually cleaned the whole registry, it became better, but not perfect. Sometimes it works from the beginning and then, after a couple of minutes, the effect appears. Sometimes it was much more than 5 or 10 seconds. I guess, it's something with the drivers. Since we got the same problem, the hardware should be okay.
So long, Torsten
edit: I can confirm, that the axes are always working. If I remember correctly (I'm on holiday, so no way to check this), the toggle buttons at the bottom of the stick as well.