multiplication formula error

Respected,
I am unable to understand why the formula in b66 is showing errors and all the functions from row 46 stops to work if I delete rows from 67.

Zohar
[email protected]

Respected Sir,
Thenk you for looking at the error but I was fortunate to solve it as it was making a circular reference(logically) with a cell that was in the other group and so it was giving error when it was used in that sheet but it was working fine when used in isolation.
AGAIN THANK YOU
Zohar