Retain Combobox Selection

I am programming some kind of database in excel and using comboboxes as drop down lists to enter some of the information in the DB. My problem is that when the file is saved, closed and then opened again, all of the comboboxes have lost their selection. I think that using the ControlSource might help but for some reason I can't find the proper syntaxe to make it works. Actually I am getting a Run time error 438: This object doesn't support this property or method.

I have included the relevant portion of my code below. Is the ControlSource property going to solve my problem? If so, what is the syntax I must use? If not, what can I do to make sure that my ComboBoxes are going to keep their selection?

ActiveSheet. OLEObjects.Add(ClassType:="Forms. ComboBox.1", Link:=False, _
DisplayAsIcon:=False, Left:=hori_offset - 220, Top:=vert_offset + 78, _
Width:=180, Height:=24.75).Select
With ActiveSheet.OLEObjects("ComboBox1").Object
.Font.Size = 14
.Font.Bold = True
.Style = fmStyleDropDownList 'Use drop-down list
.BoundColumn = 0 'Combo box values are ListIndex values
End With
With ActiveSheet.Shapes("ComboBox1")
.OLEFormat.Object.ControlSource = "Q1"
.OLEFormat.Object.ListFillRange = "M1:M8"
End With