diff -up system-config-printer-1.4.1/newprinter.py.np-traceback system-config-printer-1.4.1/newprinter.py

--- system-config-printer-1.4.1/newprinter.py.np-traceback	2013-06-07 12:40:22.819125802 +0100

+++ system-config-printer-1.4.1/newprinter.py	2013-06-07 12:40:35.549191403 +0100

@@ -868,7 +868,7 @@ class NewPrinterGUI(GtkGUI):

         if self.ppdsloader:

             self.ppdsloader.destroy ()

-            self.ppds_loader = None

+            self.ppdsloader = None

         if self.printer_finder:

             self.printer_finder.cancel ()

@@ -3418,7 +3418,7 @@ class NewPrinterGUI(GtkGUI):

     def on_tvNPMakes_cursor_changed(self, tvNPMakes):

         path, column = tvNPMakes.get_cursor()

-        if path != None:

+        if path != None and self.ppds != None:

             model = tvNPMakes.get_model ()

             iter = model.get_iter (path)

             self.NPMake = model.get(iter, 1)[0]