vba effet multiple complexe

Sub test()

Dim i, DerLigBase, lig As Integer
Dim dossier, sNomFeuille As String
Dim colFeuille As Collection
Dim rCelA As Range
Dim shAct As Worksheet
Dim FeuilleExist As Boolean

'Recherche de la dernière ligne
DerLigBase = Sheets("forf").Range("B999").End(xlUp).Row
Set colFeuille = New Collection

On Error Resume Next
'Boucle sur la plage de cellule
For Each rCelA In Sheets("forf").Range("B2:B" & DerLigBase)
    colFeuille.Add rCelA, CStr(rCelA)
Next rCelA

'Recherche de la ligne et tri dans chaque feuille
For i = 2 To DerLigBase
    dossier = Cells(i, 2).Text
    lig = Sheets(dossier).Range("J999").End(xlUp).Row
     
     
     'Copie les valeurs si non cochées
With Sheets("forf").Cells(i, "C").Resize(, 4)
  If IsEmpty(.Cells(-1)) And IsNumeric(Sheets("forf").Cells(i, 2)) Then 'colonne A vide
    Err = 0 'pour savoir si une erreur se produit
    Worksheets(dossier).Cells(lig + 1, "J").Resize(, 4) = .Value
       Worksheets(dossier).Cells(lig + 1, "O").Resize(, 3) = .Value
Worksheets(dossier).Cells(lig + 1, "R") = "dp"
Worksheets(dossier).Cells(lig + 1, "T") = 13

    If Err = 0 Then .Cells(-1) = "X"
  End If
End With


Next i

End Sub