I had very similar symptoms to this guy (pain starting in the wrists and then forearms/elbows). I have adjusted my typing habits and daily routine as follows:

* Exercise arms with light weights (~10lbs)

* Adjusted chair height

* Started using a real keyboard (I think typing on a MBP for extended periods was a big contributor to my RSI)

* Drink more water, get better sleep, get some kind of exercise

These days, I don't notice any kind of RSI pains. I think generally, RSI (for a typist) is due to combinations of stress, poor posture, lack of general wellness, etc.