Erreur 2015 avec Evaluate("DATEVALUE(""" & VDate & """)")

Dim Vdate As Date
Vdate = #7/13/2009#

Rep = DATEVALUE(Vdate)

Function TotalAchat(vID As String, DateDu As String, DateAu As String)
  ' Calcul le MONTANT TOTAL des ACHATS selon UN fournisseur donné
  ' et un ecart entre DATES
  Dim DLig As Long, C1 As String, C2 As String, C3 As String, C4 As String, MyForm As String
  MyForm = "": TotalAchat = 0
  DLig = Sheets("Stock").Range("B" & Rows.Count).End(xlUp).Row
  '=SOMMEPROD((H3:H18)*(L3:L18>=DATEVAL("13/07/2008"))*(L3:L18<=DATEVAL("13/07/2009"))*(P3:P18="KS001f"))
  C1 = "((Stock!$H3:$H" & DLig & ")"
  C2 = "*(Stock!$L3:$L" & DLig & ">=DATEVALUE(""" & Format(DateDu, "mm/dd/yyyy") & """))"
  C3 = "*(Stock!$L3:$L" & DLig & "<=DATEVALUE(""" & Format(DateAu, "mm/dd/yyyy") & """))"
  C4 = "*(Stock!$P3:$P" & DLig & "=""" & vID & """))"
  MyForm = "SUMPRODUCT" & C1 & C2 & C3 & C4
  TotalAchat = Application.Evaluate(MyForm)
End Function