External table is not in the expected format.. Was working before, now it's not.

I'm trying to look at two .iif files for comparison of their data. The following lines of code are throwing an error for me:

  'Get the two files we need. We will use the original file to verify the data in the exported file
  Set exported_file = DDT.ExcelDriver("J:\Enterprise\A_09170888_01-06.iif", "A_09170888_01-06", True)
  exported_file.Name = "exported_file"
  Set expo_driver = DDT.DriverByName("exported_file")
  
  Set original_file = DDT.ExcelDriver("J:\Enterprise\A_09170888_11-25.iif", "A_09170888_11-25", True) 
  original_file.Name = "original_file"
  Set orig_driver = DDT.DriverByName("original_file")

The error gets thrown on the Set.

"External table is not in the expected format."

The strange thing is that this was working for me previously and nothing has changed with the two files I'm using. I can go back through my Test Logs and see the successful runs of it working. Does anyone have any idea what could be the problem here? I've also tried restarting Test Complete and that didn't do it.