Seem to be having a problem with this line:

ActiveCell.FormulaR1C1 = "=SUM(rc[4]:rc[adj])"

Object Defined Error (#1004)

The basic premise is there are dates loaded into the 4 row in each of the
columns listed in the array. The Pull_Fwd function is determining if the
date range is less than the number of days entered for the pull forward, and
then only adding those quantities for each item listed (starting at D5).

Entire Script:
Public Sub Pull_Forward()
num = InputBox("Enter the range (in calendar days) you wish to include
in the Pull Forward Calculation: ")
strWeek = Module1.current_date(num)
MsgBox (strWeek)
Call Module1.Pull_Fwd(strWeek)
End Sub

Private Function current_date(num)
today = Date
today = Format(today, "mm/dd")
next_week = DateAdd("d", num, today)
next_week = Format(next_week, "mm/dd")
current_date = next_week
End Function

Private Function Pull_Fwd(strWeek) As Date
Dim adj As Integer
gcolumn = Array("H4", "I4", "J4", "K4", "L4", "M4", "N4", "O4", "P4",
"Q4", "R4", "S4", "T4", "U4", "V4", "W4", "X4", "Y4", "Z4")

count_column = 0
For i = LBound(gcolumn) To UBound(gcolumn)
sheet_date = Range(gcolumn(i)).Text
'MsgBox (sheet_date)
If sheet_date < strWeek Then
count_column = count_column + 1
End If
Next i
count_column = count_column - 1
'MsgBox (count_column)
adj = 4 + count_column
MsgBox (adj)
Range("d5").Select
ActiveCell.FormulaR1C1 = "=SUM(rc[4]:rc[adj])"
End Function

Thanks,
mb