Removing items from Combo box

I'm having trouble adding removing items from a combo box on an excel worksheet. The code (is supposed to) select an advisor name from a list on sheet named Client_Summary. There are several rows for each advisor and the code should just pick one. It does this but does not find them all, it skips some. Once an advisor is picked it populates some agency details onto sheet1 and then adds the customers. My problem is mainly that the code is skipping advisors and also I cannot get any code to work to clear the box prior to populating. I'm getting an endless list of advisors. Code below: If I include the ClearBox procedure I get Run Time Error 70 Permission Denied, however if I remove the call to this procedure, no errors just the problems mentioned above. Any help appreciated, code below:

Private Sub CBAdvisor_Change()

Dim Advisor As String
Dim intRows As Integer

Call AddAdvisor
Call ClearBox

Advisor = Me.CBAdvisor.Value
intRows = Sheets("Client_Summary").Range("A2").CurrentRegion.Rows.Count


For i = 1 To intRows

If Sheets("Client_Summary").Cells(i, 1).Value = Me.CBAdvisor.Value Then
ActiveSheet.Range("C8").Value = Sheets("Client_Summary").Cells(i, 2).Value
ActiveSheet.Range("C10").Value = Sheets("Client_Summary").Cells(i, 3).Value
ActiveSheet.Range("C12").Value = Sheets("Client_Summary").Cells(i, 4).Value

End If

Next i

End Sub

Sub AddAdvisor()

Dim i As Integer
Dim intRows As Integer


intRows = Sheets("Client_Summary").Range("A2").CurrentRegion.Rows.Count

For i = 2 To intRows

If Sheets("Client_Summary").Cells(i, 1).Value = Sheets("Client_Summary").Cells(i - 1, 1).Value Then

i = i + 1

Else

Me.CBAdvisor.AddItem Sheets("Client_Summary").Cells(i, 1)

End If

Next i

intRows = 0

PopulateCollectionFromSheet
CreateClientList

End Sub


Sub ClearBox()

Dim i As Integer

For i = Me.CBAdvisor.ListCount - 1 To 0 Step -1

Me.CBAdvisor.RemoveItem i

Next i


End Sub