#DIV/0!
means just that - you are trying to divide something by 0. So you need to structure that formula to catch that.

If B2 is blank of 0, then A1/B1 will result in #DIV/0!
but youi could error trap with...
=if(iserror(A1/B1),"",A1/B1)
or
=IF(OR(B1=0,B1=""),"",A1/B1)