This worked for me.

Sub MyQuery()
Dim db As Database
Dim qdf As QueryDef

Set db = OpenDatabase("c:\temp\db1.mdb")
Set qdf = db.QueryDefs("Query1")
qdf.Parameters("[Div]") = "Pants"
Set rst = qdf.OpenRecordset()
Debug.Print rst("Div")
End Sub

Hth,
Merjet