This page provided by LabVIEW has some useful troubleshooting points.

• "Error 0xBFF6901D Unable to load camera's XML file."  Error thrown by NI-MAX after selecting the camera
  
  • Close NI-MAX
  • Navigate to C:\Users\Public\Public Documents\National Instruments\NI-IMAQdx\Data\XML\
  • Delete everything in this folder
  • Open NI-MAX and select the camera.  It might tell you an attribute is out of range, just click 'Ok' and change it in the setting in NI-MAX.
  • Note: the items that were deleted will repopulate when NI-MAX is loaded. This is ok!