What this means is that the no label provider associated with any navigatorContent extensions has returned a text value. You can turn on debug tracing in the CNF (in the tracing tab of your launch configuration), this will give you helpful messages. And you should set a breakpoint at your label provider's getText() and getStyledText() methods to see if they are being invoked. Make sure they return a non-null value.
It looks like this is happening with an IProject resource. Are you including the org.eclipse.ui.navigator.resources plugin? Do you intend to handle the processing of resources?
Yes I added the org.eclipse.ui.navigator.resources plugin in my dependencies, and included it in the target platform and launch configuration. I did not really intend to use this plugin at first, but I thought it was almost mandatory to have it in order to handle resources properly.
I am just surprised that there is no label provider associated by default with the IProject resource that I create from the navigator "New>Project" wizard.
I will try what you advise and let you know. Tank you for that.