Array Problem

[Phil Hageman]

Worksheet "Customer": In the cells in range U19:U30 users
post values, which are acted upon by formulas in an
adjacent range X19:X30, i.e., formula in X19 acts on U19
value. Typical U range formulas:
=IF(U19="","",IF(U19<>0,(U19-V10)/(P10-V10),0))
=IF(U20="","",IF(U20<>0,(U20-V10)/(P10-V10),0))
Etc.

In cell W31 the following array formula looks at range
X19:30 creating the last value in from the X column:
{=INDIRECT(ADDRESS(MAX((ROW(19:30)*
(X19:X30<>""))),COLUMN(X:X)))}

In cell X31 the following formula shows the value created
by the array formula:
=IF(ISERROR(W31)=TRUE,"",W31)

The result: U cell value X31 shows
55% 55%
0% 0%
nothing blank
This is the desired outcome to this point.

Now the twist - I need to put link formulas in the U19:U30
cells, to bring in cell values from worksheet "Rollup";
however, the Rollup cell value is #Div/0! in some cases,
which makes the array formula in the Customer worksheet
return a blank (nothing?) - instead of a legitimate
number, say 55% if it appeared in the U column. Needed
is: if the last cell value in the U column is, as in the
above example, 55%, 0%, or blank, for the array formula to
ignore the error values, and operate normally. I cannot
figure out how to do this - Can someone help?

Thanks, Phil