There are four buttons in the middle of your indexing screen and slightly to the left that you should be using. They are B, U, B, and U and they are enclosed with <> brackets.
The first one is for marking a FIELD as blank; the second is for marking a FIELD as unreadable; the third one is for marking an entire RECORD/LINE as blank; and the last one is for marking the entire RECORD/LINE as unreadable.
EVERY LINE should have something entered for it. There is either information that is entered on the grid or if there is nothing there to index, mark the entire line as blank with the second button.
In some of the records we are getting now, the line numbers may be missing or many of the lines may be blank. DO NOT renumber the lines or add line numbers if none are present.