unable to read data from the transport connection an existing connection was forcibly closed by the remote host in postgresql !

plz help.....

this is my connection method to postgresDB

Public Function GenConnection() As NpgsqlConnection
        Dim Connection As New NpgsqlConnection("Server=" & gstrServerName & ";Port=" & gstrPort & ";Database=" & gStrDBName & ";Pooling=false;MINPOOLSIZE=0;CONNECTIONLIFETIME=0;COMMANDTIMEOUT=0;MAXPOOLSIZE=100;Username=" & gstrUserName & ";Password=" & gPassword)
        Try
            If Connection.State = ConnectionState.Open Then
                Connection.Close()
            End If
            Connection.ClearAllPools()
            Connection.Open()
            gblnValidConnection = True
            Return Connection
        Catch ex As Exception
            gblnValidConnection = False
            MsgBox(ex.Message)
        End Try
    End Function

and the above mentioned problem occuring unexpectdly in datareader and datatable ....

Public Function GetDataTable(ByVal cmdText As String) As DataTable
        Dim dt As New DataTable
        Dim command As New NpgsqlCommand(cmdText, GenConnection)
        Dim dataAdapter As New NpgsqlDataAdapter(command)
        Try
            dataAdapter.Fill(dt)
            GenConnection.Close()
            GenConnection.ClearAllPools()
            Return dt
        Catch exc As NpgsqlException
            MessageBox.Show(exc.ToString())
            ThrowNpgsqlException(exc)
        Catch ex As Exception
            MessageBox.Show(ex.ToString())
            ErrorLogging(DateAndTime.Now)
            ErrorLogging(ex.ToString)
            Dim errObj As New FrmError
            errObj.GenErr.DisplayError(ex.Message, ex.ToString)
            errObj.ShowDialog()
        End Try
    End Function

and

Public Function GetDataReader(ByVal cmdText As String) As NpgsqlDataReader
        Dim dr As NpgsqlDataReader

        Dim command As New NpgsqlCommand(cmdText, GenConnection)
        Try
            dr = command.ExecuteReader
            Return dr
        Catch exc As NpgsqlException
            ThrowNpgsqlException(exc)
        Catch ex As Exception
            ErrorLogging(DateAndTime.Now)
            ErrorLogging(ex.ToString)
            Dim errObj As New FrmError
            errObj.GenErr.DisplayError(ex.Message, ex.ToString)
            errObj.ShowDialog()
        End Try
    End Function