When trying to use Knime to convert a .CSV file that has strings in it to ARFF files I've run into what could be called a bug.
If a string has a single quote ' . Knime does not escape the character in the ARFF Writer Node. That is making the ' that appears within a string \' .
You can see this problem with the Titanic Kaggle file. If you try to run a process CSV reader to ARFF Writer. You get a file out of Knime but the WEKA application cannot read the file because of the extra ' in the string.