okay, I've got a worksheet (Individual Week Totals Tracking) that uses
an array function to call on another worksheet (Lantigua) and sums the
cells in each column holding a specific date in the Lantigua
worksheet.

Within the Lantigua worksheet are weeks of the month starting with
saturdays (i.e. week of 4-June) and within each week holds values which
are totaled at the end of each group of cells.  In the totals section
there is an IF statement to display no text if there are no values in
that week, and adds all the values if there is ANY values entered.

When the array formula calls the Lantigua worksheet, it adds the total
values of the whole month given the criterea of the column holding all
the days of the corresponding month. And it works when there are values
entered in EVERY week of the month.  But if there are no values entered
for an entire week, the array formula will read "#Value!".

Is this because of the IF statement?
Here are the formulas:

INDIVIDUAL WEEK TOTALS TRACKING
{=SUM((Lantigua!$C$2:$HJ$2>=DATEVALUE("1-Jan"))*(Lantigua!$C$2:$HJ$2<=DATEVALUE("31-Jan"))*(Lantigua!$C$5:$HJ$5))}

LANTIGUA
=IF(C5+D5+E5+F5+G5+H5+I5<=0,"",SUM(C5:I5))