Text processing

Hi, ı tried to use text processing but ı got some error message in the bag of words part.

First i ımported my text file in csv format then i transformed it into document and then trying to make a bag of words and got the error message of "Index of specified original document column is not valid! Check your settings!’ problem. How do i fix this error.
Could you help me about this problem?

Thank you for your question. Could you maybe attach a simple workflow where this happens?