Week number returns #Value error when cell is blank

Hi,

I have a calendar that populates the months by entering only the first date of the year and it will continuously populate the rest of the months according to the first date entered.

I have a row formatted to Date, DD and Week number, but the problem is, on February, if it's not leap year, the cell returns blank so the Week Number shows #Value error.

The February has a formula to identify if it is a leap year or not and it will populate if its leap year and it will be blank if not.

I have tried inserting WEEKNUM function but nothing seems to work.

Can you help please?

Thanks in advance. Please see attached sample file.