I've searched through the archives about using
worksheetfunction.Vlookup in VBA, but I'm getting an error I haven't
seen before.

I'm running Excel 2003. My routine takes a large data base, reduces
the data into an A x B table, then uses the data in the table against
a B x C table. For diagnostics and ease of following the math, both
arrays are written to a temporary worksheet and given range names.

So, my code loops though one of the named ranges, does the lookup,
then sums the result into a final array:

deptArray(i,j)=deptArray(i,j) + WorksheetFunction.VLookup
(ActiveCell.Offset(j,0), "RangeName1", k, False)

where i,j are the array bounds, RangeName1 is the named range of one
of the arrays, k is the column number of the value to return, and
activecell is the upper leftmost corner of the second named range.

The error I get is :

Runtime error '1004'

Unable to get the VLookup property of the
WorksheetFunction Class

I've got all the standard add-ins on the Excel side running, and no
available add-ins on the VBA side.

Any suggestions?

Art