Somehow the dkuReadDataset() function within the R recipe is currently not working for me. I uploaded the picture to display it. I have a working input file, but the input file does not get recognised.
It looks like you saved the output of dkuReadDataset into the variable open.
What it should look like is
open_proef_scored_prepared <- dkuReadDataset("open_proef_scored_prepared")
open <- open_proef_scored_prepared