This is to ensure you are in the correct portal row. What does the data viewer show for get(activerownumber) while the script is running?
If it is staying in the correct row you are good. Once you are in the correct row you can move around in the row by using field names and object names. The portal row will be your reference point.
If this is related to your other topic I have added an example file in the original post. Your assumption that you setup the Pop-Drop properly may have led you to believe something was wrong with the portal row reference and navigation. It is not actually needed since you stay in one active portal the entire time.