Following code works on another machine, not on mine

Private Sub CommandButton1_Click()

Dim r, c As Integer
Dim x As String

r = 4
c = 4
x = "TEST"

With Me.Controls.Add("Forms.TextBox.1")
.Left = 10
.Top = 30
.Width = 30
'.Value = "Leeg"
.ControlSource = "G7"
.ControlSource = Sheets(x).Cells(r, c)

End With
End Sub

I get a runtime error 380 : Could not set controlsource property. Invalid property value