modify kml read error message

fluegggui/plots_gui.py

@@ -209,8 +209,7 @@ class PlotsWindow(QMainWindow):
             print("Saved to: {}".format(path))
         except BaseException as e:
             known_errs = {"'NoneType' object has no attribute 'find'":
-                          "The KML streamline file appears to be inadequate. " +
-                          "Perhaps a FluEgg results file was used instead."}
+                          "Unable to read streamline file."}
             msg = QMessageBox()
             msg.setIcon(QMessageBox.Warning)
             msg.setText("Could not export KML")