ListBox parameters problem

[baddy]

I have a form with one listbox, two combo boxes and two text boxes that provide parameters for the query that feeds the listbox. The selection of parameters trough comboboxes works perfectly but the query does not pick up parameters(datefrom/dateto) form text boxes. When I remove references to combos, date parameters work just fine, but the dates are not selected when there is reference to combos. The code behind combos is as follows:

Private Sub CboStaff_AfterUpdate()
Dim vSearchString As String

vSearchString = Me.CboStaff.Text
Me.txtSearch2.Value = vSearchString
Me.MyList.Requery

What am I doing wrong?