in my last post in this thread i wrote that the DocumentVector node creates a Row (document vector) for each document in the input table. This is not true, i apologize for this misinformation. The way you used the DocumentVector node is the right way. You can apply the node on a bag of words input table. This is the way the node is ment to be used. The node should create for each unique document in this bag of words input table exactly one row (document vector).
Obviously this is not the case in your workflow. Can you give me some more information about the nodes you are using? What is the exact preprocessing chain and how do you extract the keywords? Are you using the Frequency Filter node to extract keywords? A screenshot of your workflow, or the workflow itself without data would be really helpful. I think there might be a problem but not in the DocumentVector node itself but maybe in the keyword extraction process/node. In the DocumentVector node simply the equals method of a document is used to compare them.
Sorry for the inconveniece!