Controlling row position in Input Array

In an INPUT ARRAY situation I have rows with only two fields, only one of which (the first one) is for data entry. The other is for display only. After the user enters a value in the field and moves the cursor to the next row, I check the validity of the entry in an AFTER ROW statement. If the entry is not valid, I would like to remain in the same row (after warning the user). I could not find a way to do this. I am using the SE version 4.1 (I believe). I would appreciate any suggestions. Thank you.