Error prevents Saving back to LR from DxO PhotoLab or Optics Pro 11

The plug-in used to work not a month ago but now when I call on DxO Photolab or DxO Optics Pro 11  from LR, I can edit the photo and then when I try to save back to LR Classic, I get the following error and the saved photo, as jpg or dng or tiff is not saved back into LR Classic catalogue.

"an internal error has occurred:?:0: attempt to index field 'rootfile' (a nil value)"

Thanks,

Mike