error object required

[anavakom]

can help... i get the following error -object reguired .. the code is
Sub uvecaj()
Dim a As Range
Dim b As Range
Dim c As Range
For i = 21 To 30
With Worksheets("faktura")
Set a = .Range("B" & i).Value
Set b = .Range("D" & i).Value
End With
For j = 1 To 5
Set c = Artikli.Range("A" & j).Value
If a = c Then
Set Artikli.Range("E" & j).Value = Artikli.Range("E" & j).Value + b
Else
End If
Next j
Next i
End Sub


thanks