How to call stored procedure with Germini Interbase?

Hello
I want to call a stored procedure which will allow user to update somethings. But I always cannot call stored procedure in Interbase.

I used Parameters method, but it seems that interbase cannot read my request of calling store procredure, but just execute it as a normal SQL Command. The error always shows "Invalid token: SP_Update_PW".

My stored procredure can execute successfully in IBExpert. And the transaction is successful when I use "execute SP_UPDATE_KEY ('" & strUserID xxxxxxxxxxxx" directy. But that's not what I want. I can't get return result with my proc. And also, it seems that I can't set Parameter's Direction as VarChar....Is that the same with String? (I use VarChar in my Proc).

Here is the following code. Thanks a lot

Code:

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    Sub CHIP(ByVal sender As Object, ByVal e As System.EventArgs)
        Dim cs As String = "DSN=MTM_POS"
        Dim cn As OdbcConnection = New OdbcConnection(cs)
        Dim cmd As New OdbcCommand
       
        cmd.Connection = cn
        cmd.CommandText = "SP_UPDATE_KEY"
        cmd.CommandType = CommandType.StoredProcedure
       
        Dim dbParameter As New OdbcParameter
        'PPC Key
        dbParameter = cmd.CreateParameter()
        dbParameter.ParameterName = "@PPC_KEY"
        dbParameter.Value = txtPPCKey.Text
        dbParameter.Direction = ParameterDirection.Input
        dbParameter.DbType = DbType.String
        cmd.Parameters.Add(dbParameter)
       
        'PPC Name
        dbParameter = cmd.CreateParameter()
        dbParameter.ParameterName = "@PPC_NAME"
        dbParameter.Value = txtPPCName.Text
        dbParameter.Direction = ParameterDirection.Input
        dbParameter.DbType = DbType.String
        cmd.Parameters.Add(dbParameter)       
       
        'Staff ID
        dbParameter = cmd.CreateParameter()
        dbParameter.ParameterName = "@STAFF_ID"
        dbParameter.Value = txtStaffID.Text
        dbParameter.Direction = ParameterDirection.Input
        dbParameter.DbType = DbType.String
        cmd.Parameters.Add(dbParameter)
       
        'Staff Password
        dbParameter = cmd.CreateParameter()
        dbParameter.ParameterName = "@STAFF_PW"
        dbParameter.Value = txtStaffPW.Text
        dbParameter.Direction = ParameterDirection.Input
        dbParameter.DbType = DbType.String
        cmd.Parameters.Add(dbParameter)
       
        'Result
        dbParameter = cmd.CreateParameter()
        dbParameter.ParameterName = "@RESULT"
        dbParameter.Direction = ParameterDirection.ReturnValue
        dbParameter.DbType = DbType.Int16
        cmd.Parameters.Add(dbParameter)
       
        cmd.ExecuteNonQuery()
        Dim intResult = cmd.Parameters("@RESULT").Value
        cn.Close()

    End Sub

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