I'm trying to check if a value exists inside of a range using the Find function, as follows:

        If blnMissAcc = False And blnInvalid = False And IsError(wsCoA.Range("F:F").Find(wsWorking.Cells(i, 15))) Then
            If strNote <> "" Then strNote = strNote + ", "
            strNote = strNote & "Account not in CoA"
            blnDontCare = True                                      'Account isn't in CoA but is present and valid.
        ElseIf blnMissAcc = False And blnCash = False And blnInvalid = False And wsWorking.Cells(i, 19) = "" And _
            wsWorking.Cells(i, 15) <> 5800000 And wsWorking.Cells(i, 15) <> 6511000 Then
            If strNote <> "" Then strNote = strNote + ", "
            strNote = strNote & "Missing program code - review!"
            blnMissProg = True                                      'Program missing, but good account code.
        End If
The problem is, the IsError function returns a "false" in all situations, even when the value doesn't exist. But if I try to run the Find function on its own in that case, it gives me the Error 91 "Object not set." Isn't "IsError" supposed to detect when something triggers an error?

What should I be doing instead to avoid the error messages and read that value as a "True" for the purposes of my If statement above?