Specified cast is not valid

Hi
Need some help!! Have been working on a project that lets me connect to my Ms access database and display the data in a datagrid. This bit works fine, however when i try to add a new record to a table or update a record using the edit function of the datagrid (which also works gd) i get an "Specified cast is not valid"

The code where the exception comes from

For i = 0 To e.Item.Cells.Count - 3
Line 129: strText = CType(e.Item.Cells(i).Controls(0), _ (This is the problem)
Line 130: TextBox).Text

The whole function

Function UpdateDataStore(ByVal e As DataGridCommandEventArgs) AsBoolean

Dim i, j AsInteger

Dim params(4) AsString

Dim strText AsString

Dim blnGo AsBoolean = True

j = 0

For i = 0 To e.Item.Cells.Count - 3

strText = CType(e.Item.Cells(i).Controls(0), _

TextBox).Text

If strText <> "" Then

params(j) = strText

Else

blnGo = False

lblMessage.Text = lblMessage.Text & "You forgot to enter a value"

EndIf

Next

IfNot blnGo Then

ReturnFalse

ExitFunction

EndIf



Dim strSQL AsString = "UPDATE tblMember SET " & _

"MemberFirstname = `" & params(0) & "`," & _

"MemberSurname = `" & params(1) & "`," & _

"Address = `" & params(2) & "`," & _

"MemberFirstname = `" & params(3) & "`," & _

" WHERE User ID = " & CType(e.Item.Cells(0).Controls(1), Label).Text

ExecuteStatement(strSQL)

Return blnGo

EndFunction

Any help would be fantastic