If you create a new dataset (postgresql in my case) with just filling fields and click on CREATE button
The error "Invalid number of columns in query" appear
The reason of the problem is your dataiku schema is empty.
To correct this one, click on CHECK DATA button and RELOAD SCHEMA USING DETECTED DATA button
Now, you can use your dataset after you push CREATE button :)
Can you try the following: go to your table, then Settings -> Schema -> Reload schema from table