Integrating Freescale Multi Sensor board with Arduino
So... 20 months later I stumbled upon this question, only to find out I wrote it. Awkward! Anyway, for anyone who stumbles across this question in the future, here is the answer.

The Rx pin is connected to the Bluetooth module, and as such the module will keep the pin in an idle state (either idle-high or idle-low). The Rx pin of the Arduino UNO (or the Rx0 pin on the Mega/Due) requires to be free of anything that may interfere with the upload. The Arduinos rely on the Rx pin for the sketch upload. If anything is connected to it, the IDE will freeze and nothing will be uploaded. Simply disconnect the FRDM board, upload the code, and put the board back in place. Then it should work.