NI 9214 having issue with a common-mode range error

Hey,

  I am taking readings using k-type thermocouples using the NI 9214 module in a cRio.  System works great at room temperature, but once I take the area around the thermocouples up to 300 degrees C, I keep getting the error: "A common-mode range error was detected." 

  I am using the NI 9214 in High resolution mode, with OTD disabled.  I have gone through the documentation on the error, but it is light on suggested solutions.  I am wondering if anyone else has seen this, and if so how you solved it.

Thanks!