@umutcankurt I tried to read the data with the Excel Reader under Windows but it failed. With MacOSX and several nodes I think I can read the data and also it seems there are R packages that can read them as CSV and store the results in other formats like KNIME .table or ARFF or Parquet or SQLite which you might later use.
The (new) CSV reader although had a problem also under MacOSX.
So while R might not be the easiest option there could be a workaround.