Something odd about the kindle touch (and k4nt). It seems that the third pin that we have been calling "GND" (ground) does not make a good ground. The kindle serial i/o seems to work better when another ground is used, like a metal shield. Or, you can leave off the ground connection and keep the kindle USB connected to the same computer as the serial adapter, so it uses the USB cable ground as the serial ground.
Perhaps that third pin is CTS or DTR (hardware handshake)???