Need a Cell (with formula) to be Blank if adjacent cell is blank - Help!!

I've developed a formula for a workbook "=PRODUCT(SUM(E7:E16),1/SUM(D7:D16))"

Now i want to make that cell blank for next or new dates as they giving some result
and its disturbing the Conditional formatting (Color Scales).

So what changes should i made to this formula.
This is my first workbook so please help..!!

Also the cell is showing error but giving the result fine.

Book1.xlsx

Thanks in advance.

Thanx Roy (star given)

Its working fine just with error mark, but the result is OK
Error: Formula omits adjacent cell

Should i ignore it??

@ mitrbikram

Based on your last post it seems that you are satisfied with the solution(s) you've received but you haven't marked your thread as SOLVED. I'll do that for you now but please keep in mind for your future threads that Rule #9 requires you to do that yourself. If your problem has not been solved you can use Thread Tools (located above your first post) and choose "Mark this thread as unsolved".
Thanks.

I will take care of it in future.... Thanx..!!