I see this message from the BrysonDenham test case with the setting meshIntervalNumPoints=15:
For BarycentricLagrangeInterpolator::Interpolate,Because indVarVec is not defined, it must be provided as an input!;
Changing the value to 14 removes the exception. The text of the message should be clearer. (I had to ask other folks – Jeremy – for a clue about what the issue was.) But it also seems like the code shouldn't have this issue in the first place.