Grid Erroring as if it is Adding a "Blank" Row

Hi,

We have created a custom page that contains effective dated table information in a grid.  This table contains authorization limits by department and categories.  We have "prepopulated" this table via SQL. When we go to maintain exiting department/category combinations, everything is working great, but when we go to add a new Department/category combination, the grid comes up pre-populated with a blank row.  Even if we "delete" this blank row, the database upon saving is trying to enter a blank record into the table.  Any ideas why this might be happening?

Thanks!

~Racheal