=if(sum("data range"=0,"your error value",yourformula)

??

pls. explain with

=if(iserror(hlookup(a1,myrange,2,false)),0,hlookup (a1,myrange,2,false))

or

=if(iserror(a1/b1),0,a1/b1) where b1 can be 0, #N/V, #Div0 or #Name

arno