[RyanN]

Originally Posted by Ian R.

We're using Sparkfun's SEN-11486 (https://www.sparkfun.com/products/11486)
We also tried the temperature reading using address 0x68 instead of 0x69, but we got the same result

The breakout board has the A0 pin connected to ground, so you are correct in using 0x68.

I have no idea if my code works since I no longer have an MPU-9150, but maybe it'll point out your problem.