An error occurs when enetering no Gateway username

When entering no unsername on a gateway information dialog, this error is produced.

SEVERE:
java.util.MissingResourceException: Can't find resource for bundle java.util.Pro
pertyResourceBundle, key message.gateway.username.error
at java.util.ResourceBundle.getObject(Unknown Source)
at java.util.ResourceBundle.getString(Unknown Source)
at org.jivesoftware.resource.Res.getString(Res.java:37)
at org.jivesoftware.sparkimpl.plugin.gateways.TransportRegistrationDialo
g.actionPerformed(TransportRegistrationDialog.java:156)
at org.jivesoftware.sparkimpl.plugin.gateways.TransportRegistrationDialo
g.keyPressed(TransportRegistrationDialog.java:191)
at java.awt.Component.processKeyEvent(Unknown Source)
at javax.swing.JComponent.processKeyEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.KeyboardFocusManager.redispatchEvent(Unknown Source)
at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(Unknown Source)

at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(Unknown Sour
ce)
at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(Unknown Sour
ce)
at java.awt.DefaultKeyboardFocusManager.dispatchEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)