Even if you change the sample rate in the Song->Song Setup->General->Sample Rate menu and click "Apply"? I'm sorry to hear that.
You mentioned that you have the latest firmware and drivers installed, but have you tried updating with the latest beta release as well? Like I said earlier, I fiddled around at the time, so it's entirely possible that this was what actually fixed my sample rate problem - it certainly solved some stability issues for me.
But it's a beta, so beware: I suppose the opposite might happen as well. Anyway, if you want to take the risk, here's the link:
Best of luck!