Access97 - Too Few Parameters

I am writing a simple Access 97 database but in my form/subform, I keep getting this error - Too Few Parameters.  Expected 1.  I have a main form called "frmOrders"; its fields include a ClientID, OrderDate (hidden - set to todays date); then my subform on the bottom of the screen (linked by ClientID, OrderDate) has a drop down for AgentState, and some other fields like AmtOwed, Amt Due, etc. - the subforms Control Source is "qryfrmOrders" - based on the table "tblOrders" - the key on this is ClientID, AgentState, and OrderDate.  In this scenario, there is one client with multiple AgentStates.  Everything works fine until I use the dropdown on AgentState and a choice is made, then it comes up with the error Too Few Parameters. Expected 1.  According to Microsoft, they state there is a colunn name that is incorrect but I have looked all all of the names and just cannot come up with anything.  My code for the sql statement is below - I have this same exact code with different names on another form and works perfect.

Private Sub AgentState_AfterUpdate()
Dim db As DATABASE
Dim oRecordset As Recordset
Dim szSql As String
Dim szErr As String

Set db = CurrentDb()

On Error GoTo ErrorHandler

'ISADRA  Here the code will check the tables for duplicate records and inform the user if there is a duplicate
'And also will back up one record by sending ESC so that this duplicate is not entered.
If IsNull(Me![ClientID]) Then
  MsgBox "You must first select a ClientID#!", , " Client needed for File"
  SendKeys "{ESC}"
  Exit Sub
End If

If IsNull(Me![OrderDate]) Then
  MsgBox "You must first enter a OrderDate!!", , " OrderDate needed for File"
  SendKeys "{ESC}"
  Exit Sub
End If

 

szSql = "Select * from tblOrders where AgentState = " & Me![AgentState] & " and  ClientID = " & Me![ClientID] & _
        " and OrderDate = #" & Me![OrderDate] & "#"

If IsNull(Me![AgentState]) = True Then
    Exit Sub
End If

Set oRecordset = db.OpenRecordset(szSql)
If oRecordset.RecordCount > 0 Then
    MsgBox "The State code " & Me![AgentState] & " Already exsists in the  file for " & Me![OrderDate] & _
           "!!....Please Enter a valid State Code for this Client", vbExclamation, "State Code Already Exists"
           SendKeys "{ESC}"
End If


Exit_Sub:
  db.Close
  Exit Sub
 

ErrorHandler:
MsgBox Err.Description
GoTo Exit_Sub
 
End Sub