I have put together a form with three different tables.  As long as you have at least one value in each row, there is no problem in submitting.  If you enter a couple of values at random inside the tables and leave many spaces blank, you will receive an error message when trying to submit.  So, should users be able to submit a form with null values inside a table or do you have to set it up to have default values (i.e 0)?  Or, is this something completely different that is keeping users from submitting?  Any guidance would be greatly appreciated.

Thanks