In the short term - Turn the TCS off
the TCS compares the speed of the rears to the spedd of the fronts, and if the rears are spinning faster - it thinks you're wheel spinning
HOWEVER
It's very sensitive and, like the GTR's ATTESA, it can sometimes sense if the rear tyre is nearly bald (compared to the front) which makes it look like the rear is spinning faster and BINGO - TCS!
Here's a quick list of the things I'd check
Rear Tyre wear
Tyre sizes (compare front to rears in this tool - http://www.miata.net/garage/tirecalc.html and make sure theres less than 0.5% difference)