Index: ui4/devmgr5.py
===================================================================
--- ui4/devmgr5.py	(revision 13589)
+++ ui4/devmgr5.py	(working copy)
@@ -1895,8 +1895,8 @@
                 self.updatePrintController()
                 self.cur_device.sendEvent(e, self.cur_printer)
             else:
-                log.error("Start/Stop printer operation failed")
-
+#                log.error("Start/Stop printer operation failed")
+                FailureUI(self, self.__tr("<b>Start/Stop printer queue operation fails.</b><p>Try after adding user to \"lpadmin\" or \"sys\" or \"lp\" group.</p>"))
         finally:
             endWaitCursor()
 
@@ -1925,9 +1925,9 @@
                 self.updatePrintController()
                 self.cur_device.sendEvent(e, self.cur_printer)
             else:
-                log.error("Reject/Accept jobs operation failed")
+#                log.error("Reject/Accept jobs operation failed")
+                FailureUI(self, self.__tr("<b>Accept/Reject printer queue operation fails.</b><p>Try after adding user to \"lpadmin\" or \"sys\" or \"lp\" group.</p>"))
 
-
         finally:
             endWaitCursor()
 
@@ -1938,7 +1938,8 @@
         try:
             result = cups.setDefaultPrinter(self.cur_printer.encode('utf8'))
             if not result:
-                log.error("Set default printer failed.")
+#                log.error("Set default printer failed.")
+                FailureUI(self, self.__tr("<b>Set printer queue as default operation fails.</b><p>Try after adding user to \"lpadmin\" or \"sys\" or \"lp\" group.</p>"))
             else:
                 self.updatePrintController()
                 if self.cur_device.device_type == DEVICE_TYPE_PRINTER: