sorry I couldn;t help, still a bit new at this myself.

If you're still getting a mismatch, then mayb see if something like
this works:

Dim i as Double
dim k as Double
k = 0
For i = 2 to 100
if isNumeric(k + thisworkbook.worksheets("sheet1").cells(1, i)) then
k = k + thisworkbook.worksheets("sheet1").cells(1, i)
end if
next i