[MacPerl] NavigationLib?

[daltman]

I just tried to fire up the newly acquired MacPerl 5.6.1b2 and was greeted with a 
dialog box saying that it couldn't find "NavigationLib". WHAT is that? It's not on any 
of my (admittedly antique) machines running everything from System 6.1 to OS 9.0.4 and 
searching Apple, Tucows, AMUG, VersionTracker, and SourceForge produced no results. 
Any idea what this message means?