Thanks - moving that folder gets me further.
I changed:
Dim worldLayer As New PersonalGeoDatabaseFeatureLayer("..\..\SampleData\Data\JORWD6gdb.mdb", Nothing, Nothing, "Mains")
to
Dim s57Source As New S57FeatureLayer("X:\CDR Maps\ENC\South China Sea\EA200003\ENC_ROOT\EA200003.000", "ID","","","Geom")
I still can't see my layer yet - when the map does a refresh I see:
"A first chance exception of type 'System.Reflection.TargetInvocationException' occurred in mscorlib.dll"
I am presuming that is because I have no idea what the idColumnName or geometryColumnName is in the S57 file that I have. I presume I need to look at FeatureSource to find all the column names & pick which one is the one I need. Or dig up my other S57 reader and see if that gives me column names.